The play had already been on for quite some time when we at the New Theatre.A. have arriv

问题补充：

The play had already been on for quite some time when we at the New Theatre.

A. have arrived

B. arrived

C. had arrived

D. arrive

答案：

A. have arrived

(答案→)B. arrived

C. had arrived

D. arrive

解析：主句的谓语动词用过去完成时，when从句的谓语动词要用一般过去时。而不能用过去完成时。