Question

They were about to leave       it began to rain.

A．before

B．durning

C．while

D．when

Answer 1

D

試題分析：考查連詞。be about to do sth...when...,正要做某事的時候，這時（突然）...。A.before在...之前，趁...還未，不等...就  B.durning在...期間  C.while 當...的時候，盡管 D.when當...的時候，這時（突然）。句意：他們正要離開時，天開始下雨。
點評：本題要注意特殊句型結構：be about to do sth...when...,正要做某事的時候，這時（突然）...。類似的還有：be doing sth...when...，正在做某事的時候，這時（突然）...。
即學即練：I was about to get out the room       the door was opened ．
A.when      B.while     C.before    D.as
選A