I was about to leave my house the telephone rang.A. whileB. asC. whenD. and

问题补充：

I was about to leave my house the telephone rang.

A. while

B. as

C. when

D. and

答案：

A. while

B. as

(答案→)C. when

D. and

解析：句意：我正要离开家，这里电话铃响了。某一动作正在发生或正要发生的时候，突然间、偶然地发生了另一动作，此时要用when来引导另一动作,并且这个when从句不可放到句首去。