beginning
All a b c d e f g h i j k l m n o p q r s t u v w x y z
All CEFR A1 A2 B1 B2 C1 C2
Content locale
EN Anglais BN Bengali HI Hindi ES Espagnol FR Français DE Allemand RU Russe ZH Chinois JA Japonais
All Vocabulary Cards All Vocabularies
A1 noun /bɪˈɡɪnɪŋ/

beginning

début
Meaning
The start or first part of something.
Example
The beginning of the story was very interesting.
Le début de l'histoire était très intéressant.
A1 noun /dʒuˈlaɪ/

July

juillet
Meaning
the seventh month of the year in the Gregorian calendar
Example
July is often the hottest month of the year.
Juillet est souvent le mois le plus chaud de l’année.
A1 noun /ruːm/

room

chambre
Meaning
A space within a building enclosed by walls, floor, and ceiling
Example
She decorated her room with bright colors.
Elle a décoré sa chambre avec des couleurs vives.
A1 adverb /ˈkwɪk.li/

Quickly

rapidement; vite
Meaning
at a fast speed; with little delay; rapidly
Example
He quickly finished his homework.
Il a rapidement fini ses devoirs.
A1 verb /peɪ/

pay

payer
Meaning
to give money in exchange for goods or services
Example
I need to pay my bills on time.
Je dois payer mes factures à temps.
A1 pronoun /ˈɛvribɒdi/

everybody

tout le monde
Meaning
all people; everyone
Example
Everybody enjoyed the party.
Tout le monde a apprécié la fête.
A1 noun/verb /ˈkʊkɪŋ/

cooking

cuisine
Meaning
the process of preparing food by heating it
Example
Cooking is one of my favorite hobbies.
La cuisine est l'un de mes passe-temps préférés.
A1 noun /bɔɪ/

boy

garçon
Meaning
a male child or young male person
Example
The boy ran across the playground.
Le garçon courait à travers la cour de récréation.
A1 interjection /waʊ/

wow

expression de surprise
Meaning
used to express great surprise, admiration, or pleasure
Example
Wow, that performance was amazing!
Wow, cette performance était incroyable!
A1 pronoun /ɪt/

it

ça
Meaning
used to refer to a thing, animal, or idea previously mentioned or easily identified
Example
It is raining outside.
Il pleut dehors.
A1 noun /mɪlk/

Milk

lait
Meaning
a white liquid produced by cows, goats, or other mammals, used as food
Example
Children need to drink milk for strong bones.
Les enfants doivent boire du lait pour avoir des os solides.
A1 noun /lænd/

Land

terre; sol
Meaning
the part of the earth's surface that is not covered by water; an area of ground, soil, or earth
Example
The farmer worked hard to cultivate his land and grow healthy crops.
Le fermier a travaillé dur pour cultiver sa terre et faire pousser des récoltes saines.
A1 noun /ˈpeɪ.pər/

paper

papier, document, travail de recherche
Meaning
A material manufactured in thin sheets from the pulp of wood or other fibrous substances, used for writing or printing on.
Example
The student submitted his research paper on artificial intelligence.
L'étudiant a soumis son article de recherche sur l'intelligence artificielle.
A1 noun, verb /hɛd/

head

tête / chef
Meaning
The upper part of the human body or to lead or be in charge of something.
Example
She turned her head to look out the window.
Elle tourna sa tête pour regarder par la fenêtre.
A1 noun /pɔɪnt/

Point

point; détail; but
Meaning
a particular detail, idea, or fact; the sharp end of something
Example
What's the point of arguing about this issue?
Quel est le point de discuter de cette question?
A1 verb /wɒʃ/

wash

laver
Meaning
to clean with water; to remove dirt
Example
Please wash your hands before eating.
S'il vous plaît, lavez vos mains avant de manger.
A1 noun /sʌn/

son

fils
Meaning
a male child of a parent
Example
His son is very talented in music.
Son fils est très talentueux en musique.
A1 determiner/pronoun /əˈnʌðər/

another

autre
Meaning
one more person or thing of the same type
Example
Can I have another cup of tea?
Puis-je avoir une autre tasse de thé ?
A1 verb /send/

send

envoyer
Meaning
to cause something to go or be taken to a particular destination; to transmit
Example
I will send you an email with the details.
Je vais vous envoyer un email avec les détails.
A1 noun /ˈfɑːðər/

father

bonheur
Meaning
A male parent of a child.
Example
His father taught him how to ride a bicycle.
Elle ne pouvait pas cacher son bonheur lorsqu'elle a reçu le prix.
A1 adverb /ˈɔːl.weɪz/

Always

toujours; pour toujours; à tout moment
Meaning
at all times; on all occasions; forever
Example
She always arrives early to work.
Elle arrive toujours tôt au travail.
A1 adjective /bɪɡ/

big

grand
Meaning
large in size, extent, or importance
Example
They moved into a big house with plenty of space.
Ils ont déménagé dans une grande maison avec beaucoup d'espace.
A1 noun ˈfoʊtoʊz

Photos

photos
Meaning
Photographs; pictures taken with a camera.
Example
Adding photos to a family tree makes it more personal.
Ajouter des photos à un arbre généalogique le rend plus personnel.
A1 noun /ˈwɪn.doʊ/

Window

fenêtre
Meaning
an opening in a wall fitted with glass to let in light and air
Example
Please open the window for fresh air.
s'il vous plaît ouvrez la fenêtre pour de l'air frais.
A1 noun /ˈsʌn.deɪ/

sunday

dimanche
Meaning
The day of the week between Saturday and Monday; often considered a day of rest or worship.
Example
We usually relax at home on Sunday.
Nous nous détendons généralement à la maison le dimanche.
A1 noun /kæt/

Cat

chat
Meaning
a small domesticated carnivorous mammal with soft fur, a short snout, and retractile claws
Example
The cat sat on the windowsill watching birds.
Le chat s'est assis sur le rebord de la fenêtre en regardant les oiseaux.
A1 adverb /soʊ/

so

tellement
Meaning
to such a degree or extent
Example
She was so happy with the gift.
Elle était tellement heureuse avec le cadeau.
A1 noun /ˈdɪnər/

Dinner

dîner
Meaning
the main meal of the day, typically eaten in the evening
Example
The family gathered for dinner at 7 PM.
La famille s'est réunie pour le dîner à 19 heures.
A1 adjective /lɔːŋ/

Long

long
Meaning
having great length; extended in distance or time
Example
The long road stretched for miles ahead.
La longue route s'étendait sur des kilomètres.
A1 determiner/pronoun /boʊθ/

both

les deux
Meaning
referring to two people or things together
Example
Both of the children were excited about the trip.
Les deux enfants étaient excités à propos du voyage.
A1 verb /steɪ/

stay

rester
Meaning
to remain in the same place; to continue being
Example
Please stay here until I return.
S'il vous plaît, restez ici jusqu'à ce que je revienne.
A1 noun /end/

End

fin; conclusion; terme;
Meaning
the final part of something; termination or conclusion
Example
The end of the movie was unexpected and left everyone surprised.
La fin du film était inattendue et a laissé tout le monde surpris.
A1 verb /set/

set

placer
Meaning
to put or place something in a position; to establish
Example
She set the book on the table.
Elle a mis le livre sur la table.
A1 conjunction /bɪˈkɔːz/

because

parce que
Meaning
for the reason that; since
Example
He stayed home because it was raining.
Il est resté à la maison parce qu'il pleuvait.
A1 adjective /kaɪnd/

Kind

gentil; compatissant
Meaning
gentle; caring; compassionate; showing sympathy
Example
He is a kind person who always helps others.
C'est une personne gentille qui aide toujours les autres.
A1 adverb /əˈraʊnd/

Around

autour; autour de; environ
Meaning
in a circle; on all sides; in the vicinity; approximately
Example
Look around and you will see many beautiful flowers.
Regarde autour et tu verras beaucoup de belles fleurs.
A1 verb /keɪm/

came

venu
Meaning
past tense of 'come'
Example
She came to the party on time.
Elle est venue à la fête à l'heure.
A1 noun /flɔːr/

floor

sol
Meaning
the lower surface of a room, on which one may walk
Example
The floor was covered with a soft carpet.
Le sol était couvert d'un tapis doux.
A1 adjective /red/

Red

rouge
Meaning
having the color of blood or fire; of the color red
Example
She wore a beautiful red dress to the party.
Elle portait une belle robe rouge à la fête.
A1 noun /ɑːrm/

Arm

bras
Meaning
the upper limb of the human body from the shoulder to the hand
Example
She raised her arm to ask a question.
Elle a levé son bras pour poser une question.
A1 noun/verb /bæŋk/

bank

banque
Meaning
an institution where money is kept and managed; or to tilt in movement (like an airplane or riverbank)
Example
She deposited the money in the bank.
Elle a déposé l'argent à la banque.
A1 interjection /haɪ/

hi

salut
Meaning
a friendly greeting used when meeting someone
Example
Hi, it's nice to meet you!
Salut, c'est un plaisir de te rencontrer !
A1 noun /ɑːrt/

art

art
Meaning
the expression or application of human creative skill and imagination
Example
She studied art at the university.
Elle a étudié l'art à l'université.
A1 noun /ˈteɪbəl/

table

table
Meaning
A piece of furniture with a flat top and legs, used for working at or placing items on.
Example
They placed the documents on the table.
Ils ont posé les documents sur la table.
A1 number /ˌfɪfˈtiːn/

fifteen

quinze
Meaning
the number 15
Example
There are fifteen students in the class.
Il y a quinze étudiants dans la classe.
A1 noun/verb /maɪnd/

mind

esprit / prendre soin
Meaning
the part of a person that enables them to think, feel, and reason; to pay attention or take care
Example
Please mind the gap between the train and the platform.
Veuillez faire attention à l'écart entre le train et le quai.
A1 adverb /ðeər/

There

là
Meaning
in or at that place; to that place
Example
I will meet you there at 5 PM.
Je te rencontrerai là-bas à 17h.
A1 adjective /juːzd/

used

usé
Meaning
having already been used
Example
This is a used car.
C'est une voiture usée.
A1 verb /niːd/

need

avoir besoin
Meaning
to require something; to be in want of
Example
I need help with my homework.
J'ai besoin d'aide pour mes devoirs.
A1 noun, verb /bʊk/

book

livre / réserver
Meaning
A set of written, printed, or blank pages fastened together; to arrange for someone to have a seat, room, or ticket in advance.
Example
I booked a table at the restaurant for dinner.
J'ai réservé une table au restaurant pour le dîner.
A1 pronoun /jɔːr/

your

votre
Meaning
used to indicate possession or association
Example
Your book is on the table.
Votre livre est sur la table.
A1 noun /eɡ/

Egg

œuf
Meaning
an oval object laid by female birds, reptiles, fish, and insects, used as food
Example
I had scrambled eggs for breakfast this morning.
Ce matin, j'ai mangé des œufs brouillés au petit-déjeuner.
A1 adjective /ˈjeloʊ/

Yellow

jaune; lâche
Meaning
having the color of the sun or gold; cowardly
Example
The yellow flowers bloomed in spring.
Les fleurs jaunes ont fleuri au printemps.
A1 adjective /ˈsɔːri/

sorry

désolé
Meaning
feeling regret or sympathy
Example
She felt sorry for what had happened.
Elle se sentait désolée pour ce qui s'était passé.
A1 adverb /təˈmɒroʊ/

Tomorrow

demain
Meaning
on the day after today; in the future
Example
Tomorrow we will visit the museum.
Demain, nous visiterons le musée.
A1 pronoun /jɔːrz/

yours

le vôtre
Meaning
belonging to or associated with the person or people that the speaker is addressing
Example
This pen is yours.
Ce stylo est le vôtre.
A1 adverb /weər/

Where

Où
Meaning
In or to what place or position; used to inquire about location
Example
Where did you put my keys?
Où as-tu mis mes clés ?
A1 verb /biː/

be

être
Meaning
To exist, to occur, or to have a particular quality.
Example
She wants to be a doctor.
Elle veut être médecin.
A1 verb /hoʊld/

hold

tenir
Meaning
to grasp or carry something; to maintain a position
Example
Please hold my hand.
s'il vous plaît, tenez ma main.
A1 adjective /kuːl/

cool

frais, calme, impressionnant
Meaning
moderately cold; calm and composed; fashionable or impressive
Example
She kept a cool head during the crisis.
Elle a gardé son calme pendant la crise.
A1 title /mɪz/

ms

Mme
Meaning
a title used before a woman's name, regardless of marital status
Example
Ms. Akter will give a speech at the seminar.
Mme Akter donnera un discours lors du séminaire.
A1 determiner, pronoun, adverb /ɔːl/

all

tout
Meaning
the whole quantity or extent of something; every one of something
Example
She spent all her money on books.
Elle a dépensé tout son argent en livres.
A1 noun /noʊz/

nose

nez
Meaning
the part of the face that contains the nostrils and is used for breathing and smelling
Example
He has a sharp nose and can smell things from far away.
Il a un nez pointu et peut sentir les choses de loin.
A1 verb /sɔ/

saw

couper avec une scie
Meaning
to cut with a saw; to use a cutting tool
Example
The carpenter saws the wood into pieces.
Le charpentier coupe le bois en morceaux.
A1 adjective /ˈbjuː.tɪ.fəl/

Beautiful

magnifique; beau; charmant;
Meaning
pleasing to the senses; attractive; having qualities that give great pleasure
Example
She has a beautiful voice that captivates everyone.
Elle a une voix magnifique qui captive tout le monde.
A1 noun /ɪɡˈzɑːm.pəl/

example

exemple
Meaning
a thing or person regarded as a model to be followed or avoided
Example
He is a good example of a hardworking student.
Il est un bon exemple d'un étudiant travailleur.
A1 adjective /kwɪk/

Quick

rapide
Meaning
fast; rapid; swift; happening in a short time
Example
She gave a quick answer to the teacher's question.
Elle a donné une réponse rapide à la question de l'enseignant.
A1 preposition /θruː/

through

à travers de
Meaning
moving in one side and out the other side of something
Example
The train passed through the tunnel.
Le train est passé à travers le tunnel.
A1 verb /ˈhæpən/

happen

arriver
Meaning
to occur or take place; to come about by chance
Example
What happened at the meeting yesterday?
Qu'est-ce qui est arrivé à la réunion hier ?
A1 noun ˈfjuː.tʃər

future

futur
Meaning
The time or a period of time following the moment of speaking or writing; time regarded as still to come.
Example
Future projects depend on strategic planning.
Les projets futurs dépendent de la planification stratégique.
A1 noun /aɪˈdiː.ə/

Idea

idée; concept; suggestion
Meaning
a thought or suggestion as to a possible course of action; a concept or mental impression
Example
She had a brilliant idea for solving the company's efficiency problem.
Elle avait une idée brillante pour résoudre le problème d'efficacité de l'entreprise.
A1 determiner/pronoun/conjunction/adverb /ˈaɪðər/ or /ˈiːðər/

either

soit l'un
Meaning
Used to indicate a choice between two alternatives.
Example
You can either call me tonight or send me an email.
Vous pouvez soit m'appeler ce soir, soit m'envoyer un e-mail.
A1 noun /ˈlet.ər/

Letter

lettre; caractère
Meaning
a character representing one or more of the sounds used in speech; a written message, typically sent in an envelope
Example
She wrote a letter to her grandmother.
Elle a écrit une lettre à sa grand-mère.
A1 noun /kɑːrd/

card

carte
Meaning
A small, flat piece of stiff paper or thin cardboard used for various purposes, such as identification, greetings, or playing games.
Example
She handed me her business card after the meeting.
Elle m'a remis sa carte de visite apres la reunion.
A1 article /æn/

an

un/une
Meaning
used before a noun to refer to a non-specific item that begins with a vowel sound
Example
She ate an apple for breakfast.
Elle a mangé une pomme au petit déjeuner.
A1 verb /wɪʃ/

wish

souhaiter
Meaning
to want something to happen; to desire or hope for
Example
I wish I could fly like a bird.
Je souhaite pouvoir voler comme un oiseau.
A1 verb, adjective /oʊn/

own

posséder
Meaning
to possess something; belonging to oneself
Example
She owns a beautiful house in the city.
Elle possède une belle maison en ville.
A1 adjective/adverb /ɪˈnʌf/

enough

suffisant
Meaning
as much or as many as required
Example
We have enough food for everyone.
Nous avons suffisamment de nourriture pour tout le monde.
A1 conjunction /waɪl/

while

pendant que
Meaning
during the time that something is happening
Example
She was reading while waiting for the bus.
Elle lisait pendant qu'elle attendait le bus.
A1 noun ˈflaʊərz

Flowers

fleur
Meaning
The reproductive structures of plants that provide nectar for butterflies.
Example
Butterflies are attracted to colorful flowers.
Les papillons sont attirés par les fleurs colorées.
A1 noun /reɪn/

Rain

pluie
Meaning
water that falls from clouds in small drops
Example
The heavy rain forced us to stay indoors.
La pluie forte nous a obligés à rester à l'intérieur.
A1 verb /kliːn/

clean

nettoyer
Meaning
To make something free from dirt, marks, or mess.
Example
She cleaned the kitchen before the guests arrived.
Elle a nettoyé la cuisine avant l'arrivée des invités.
A1 adjective /əˈfreɪd/

afraid

effrayé
Meaning
feeling fear or anxiety; worried that something undesirable will happen
Example
She was afraid of the dark.
Elle avait peur du noir.
A1 noun /skuːl/

school

école
Meaning
An institution for educating children; also a group of people sharing the same ideas or discipline.
Example
The children walked to school together.
Les enfants sont allés à l'école ensemble.
A1 noun /ˈrɪv.ər/

River

rivière
Meaning
a large natural stream of water flowing in a channel to the sea, a lake, or another river
Example
The river flows through the valley and into the ocean.
La rivière coule à travers la vallée et se jette dans l'océan.
A1 adjective /waɪt/

White

blanc; pur
Meaning
of the color of snow or milk; pale; pure
Example
She wore a beautiful white dress to the wedding.
Elle portait une belle robe blanche au mariage.
A1 adverb /waɪ/

Why

pourquoi
Meaning
For what reason or purpose; used to ask about the cause of something
Example
Why are you late today?
Pourquoi es-tu en retard aujourd'hui?
A1 noun /ˈsændwɪtʃ/

sandwich

sandwich
Meaning
two pieces of bread with food such as meat, cheese, or salad between them
Example
I made a chicken sandwich for lunch.
J'ai fait un sandwich au poulet pour le déjeuner.
A1 adjective /ˈhæpi/

happy

heureux
Meaning
feeling or showing pleasure, contentment, or joy
Example
She was very happy to receive the gift.
Elle était très heureuse de recevoir le cadeau.
A1 adjective /ˈfʌn.i/

Funny

drôle; étrange; amusant;
Meaning
humorous; strange; amusing;
Example
He told a funny joke that made everyone laugh.
Il a raconté une blague drôle qui a fait rire tout le monde.
A1 noun /ɡeɪm/

game

jeu
Meaning
An activity or sport played for amusement, competition, or skill.
Example
They played a football game in the afternoon.
Ils ont joué à un match de football l'après-midi.
A1 adjective /ˈiːzi/

easy

facile
Meaning
not difficult; requiring little effort
Example
The exam was surprisingly easy.
L'examen était étonnamment facile.
A1 noun /ˈkʌn.tri/

country

pays
Meaning
a nation with its own government and borders
Example
Bangladesh is a beautiful country with rich culture.
Le Bangladesh est un beau pays avec une culture riche.
A1 pronoun /aʊər/

our

notre
Meaning
belonging to or associated with the speaker and one or more other people
Example
This is our house.
C'est notre maison.
A1 noun /bred/

Bread

pain
Meaning
a food made from flour, water, and yeast mixed together and baked
Example
She bought fresh bread from the bakery.
Elle a acheté du pain frais à la boulangerie.
A1 noun /siː/

Sea

mer
Meaning
a large body of salt water that covers most of the earth's surface
Example
We went swimming in the sea.
Nous sommes allés nager dans la mer.
A1 noun /ˈbaɪ.sɪ.kəl/

Bicycle

vélo
Meaning
A vehicle with two wheels that you pedal to make it move
Example
She rides her bicycle to work every day.
Elle monte son vélo pour aller au travail tous les jours.
A1 preposition /ɪn ˈfrʌnt əv/

in front of

devant
Meaning
positioned before or ahead of something; facing or located at the forward side of a person or object
Example
She stood in front of the building.
Elle se tenait devant le bâtiment.
A1 adjective, adverb, pronoun /moʊst/

most

la plupart
Meaning
the greatest in amount, degree, or number
Example
Most people like to relax on weekends.
La plupart des gens aiment se détendre le week-end.
A1 preposition /baɪ/

by

par
Meaning
indicating the agent performing an action, or the means of achieving something
Example
The book was written by a famous author.
Le livre a été écrit par un auteur célèbre.
A1 noun /ˈmjuːzɪk/

music

musique
Meaning
vocal or instrumental sounds combined to produce harmony, melody, or rhythm
Example
She loves listening to classical music.
Elle adore écouter de la musique classique.
A1 noun /ˈaʊər/

hour

heure
Meaning
A period of time equal to 60 minutes.
Example
The meeting lasted for two hours.
La réunion a duré deux heures.
A1 interjection /baɪ/

bye

au revoir
Meaning
used to say goodbye; a short and informal farewell
Example
I said bye to her before leaving.
Je lui ai dit au revoir avant de partir.
A1 verb /θæŋk/

Thank

remercier
Meaning
to express gratitude or appreciation to someone
Example
She thanked her teacher for the extra help.
Elle a remercié son professeur pour l'aide supplémentaire.
A1 noun /aɪ/

Eye

œil; vision
Meaning
the organ of sight; the ability to see
Example
Her eyes sparkled with joy.
Ses yeux brillaient de joie.
A1 noun /taɪm/

time

temps
Meaning
a measured or measurable period during which an action, process, or condition exists or continues
Example
I don’t have enough time to finish the project.
Je n'ai pas assez de temps pour terminer le projet.
A1 noun/verb /ˈraɪ.tɪŋ/

writing

bonheur
Meaning
The activity of putting words on paper or composing text; the written form of communication.
Example
She spends hours every day on her creative writing.
Elle n'a pas pu cacher son bonheur quand elle a reçu le prix.
A1 adjective /əʊˈkeɪ/

okay

d'accord
Meaning
used to express agreement or acceptance
Example
It's okay to leave early today.
Il est d'accord de partir tôt aujourd'hui.
A1 adverb /ˈɔːlsoʊ/

also

aussi
Meaning
in addition; too
Example
She sings beautifully and also plays the guitar.
Elle chante magnifiquement et joue aussi de la guitare.
A1 article /ðə/

the

le
Meaning
used to specify a noun as something already mentioned or known
Example
The sun rises in the east.
Le soleil se lève à l'est.
A1 noun /ˈdænsɪŋ/

dancing

la danse
Meaning
the activity of moving the body rhythmically to music
Example
They spent the evening dancing at the party.
Ils ont passé la soirée à danser à la fête.
A1 adjective /ˈtʃɒk.lət/

Chocolate

chocolat
Meaning
a dark brown color like chocolate; the color of cocoa
Example
The chocolate brown sofa looks elegant in the living room.
Le canapé marron chocolat semble élégant dans le salon.
A1 verb /bɪˈliːv/

believe

croire
Meaning
to think that something is true; to have faith in
Example
I believe in hard work and dedication.
Je crois au travail acharné et au dévouement.
A1 noun /wiːk/

week

semaine
Meaning
a period of seven days
Example
I will finish the project by the end of the week.
Je finirai le projet d'ici la fin de la semaine.
A1 noun /triː/

tree

arbre
Meaning
a large plant with a trunk, branches, and leaves
Example
The tree in our backyard is over a hundred years old.
L'arbre dans notre jardin a plus de cent ans.
A1 noun /ˈvɛdʒ.tə.bəl/

vegetable

bonheur
Meaning
a plant or part of a plant used as food
Example
I eat vegetables every day for health.
Elle ne pouvait cacher son bonheur lorsqu'elle a reçu le prix.
A1 pronoun /ˈnʌθɪŋ/

nothing

rien
Meaning
not anything; no thing
Example
She has nothing to worry about.
Elle n'a rien à craindre.
A1 adverb /ˈsʌm.taɪmz/

Sometimes

parfois
Meaning
at times; occasionally; now and then
Example
Sometimes I go for a walk in the evening.
Parfois, je me promène le soir.
A1 verb /meɪk/

make

faire
Meaning
to create, produce, or construct something
Example
I make coffee every morning.
Je fais du café chaque matin.
A1 adverb /naʊ/

now

maintenant
Meaning
at the present moment or time
Example
I am studying now.
Je suis en train d'étudier maintenant.
A1 verb pleɪ

play

jouer un rôle
Meaning
To have a role or function in a situation; to contribute to something.
Example
Artemis will play a crucial role in Mars exploration.
Artemis jouera un rôle crucial dans l'exploration de Mars.