undergo的过去分词是____

The planes have to undergo _____ safety checks.

The travelers (undergo) ______ many difficulties on their trip to the Middle East last year.

undergo the efforts of childbirth<br/>____? A: derive B: labor C: respond

undergo<br/>the efforts of childbirth ____? A: derive B: labor C: respond

Ten years _______a decade. A: constitutes B: arise C: familia D: undergo

The explorers had to ___ much suffering. A: undergo B: go C: underwent D: undergone

The driver was confused by the _______road signs. A: ewildering B: undergo C: ea D: familia

不少人退休后会有失落感，我们应该帮助、关心他们。(retire, undergo)

I need to _______about the price of tickets. A: inquire B: constitute C: mysterious D: undergo