directly involved in the most active or dangerous part of something
directamente involucrado en la parte más activa o peligrosa de algo (directamente involucrado en la parte más activa o peligrosa de algo)
"Doctors were on the front line during the pandemic."
"Los médicos estuvieron en la primera línea durante la pandemia." (Los médicos estuvieron **en la primera línea** durante la pandemia.)
in prison
to keep one's plans or ideas secret
to be so worried or upset that you don't know what to do
to persuade someone to do something
to carefully consider the advantages and disadvantages of so...
to understand the overall situation or goal