to have a surgical operation
sich einer Operation unterziehen (zikh ainar operatsion untertsihen)
"He had to go under the knife to fix his knee injury."
"Er musste sich einer Operation unterziehen, um seine Knieverletzung zu beheben." (er musste zikh ainar operatsion untertsihen um zayne knieverletzung tsu beheben)
to return to the right path after a mistake or setback
learning by experimenting and correcting mistakes
an unplanned or spontaneous decision or action
to start working hard on something
to arrest or catch someone doing something illegal
to verify that someone or something is doing well