Helen her keys in the office so she had to wait until her husband home. A. has left; com

问题补充：

Helen her keys in the office so she had to wait until her husband home.

A. has left; comes

B. left; had come

C. had left; came

D. had left; would come

答案：

A. has left; comes

B. left; had come

(答案→)C. had left; came

D. had left; would come

解析：考察时态。根据句意可知，Helen因为先把钥匙丢在了办公室，所以她要等她的丈夫回家。

所以leave发生在had to wait之前，即过去的过去，用过去完成时，第二空是until引导的时间状语从句，从句中用一般过去时表示过去将来。