I was about to tell him the secret someone patted me on the shoulder.A. asB. untilC. whi

问题补充：

I was about to tell him the secret someone patted me on the shoulder.

A. as

B. until

C. while

D. when

答案：

A. as

B. until

C. while

(答案→)D. when

解析：句意：我正准备告诉他这个秘密这时有人拍了拍我的肩膀。句式be about to do …when…意为：正准备做某事这时……。故选D。

考点: 考查固定句式的用法。