问题
选择题
.He was about to leave ______the telephone rang; ______was from his mother.
A．when; that
B．before; which
C．when; it
D．before; this
答案
答案：C
句意：他即将离开这是电话响了，是母亲打来的。句型： be about to do …when，即将做某事，正在那时，第二空用it ，指代前面的电话，所以选C。