这道题为什么不能选while?theydecidewhichcollegetogoto,studentsshouldresearchtheadmissionprocedures.A.AsB.WhileC.UntilD.Once这道题的答案是once,为什么不能选while?

Question

这道题为什么不能选while?
__ they decide which college to go to,students should research the admission procedures.
A.As B.While C.Until D.Once
这道题的答案是once,为什么不能选while?

Answer 1

while是同时发生.
当...的时候,和...同时
She listened closely while he read the letter.
他读信时,她听得很仔细.
I'll take care of your children while you are away.
你不在时我会照顾你的孩子的.
We must strike while the iron is hot.
我们必须趁热打铁.