----Why did you go back to the shop?-----I left my friendthere.A. waitingB. to waitCwai

问题补充：

----Why did you go back to the shop?

-----I left my friendthere.

A. waiting

B. to wait

Cwaits

Dwaited

答案：

(答案→)A. waiting

B. to wait

C. waits

D. waited

解析：考查动词-ing形式作宾语补足语。Leave sb.doing sht.时某人做某事。