Helen her keys in the office so she had to wait until her husband home.
A. has left; es
B. left; had e
C. had left; came
D. had left; would e
网友回答
A. has left; es
B. left; had e
(答案→)C. had left; came
D. had left; would e
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。