to have surgery
sich einer Operation unterziehen (zikh ainar operatsion untertsien)
"She has to go under the knife for her knee problem."
"Sie muss sich wegen ihres Knieproblems einer Operation unterziehen." (zi mus zikh wegen ires kniproblems ainar operatsion untertsien)
to find the real reason or cause of something
to make something less forceful or intense
a period of difficulty or trouble
To be very sure or confident about something.
to reverse a negative situation and make it positive
to make someone jealous