I coutdn't have got to the meeting on time an earlier train.
A. if I had not caught
B. unless I had caugh
C. if ! did not catch
D. unless I caugh
网友回答
A. if I had not caught
(答案→)B. unless I had caugh
C. if ! did not catch
D. unless I caugh
解析： if．．．not和unless有时也不能互相替换。unless不能用于“由于未发生B而发生A”的句子里，如：1 will be quite斟ad if she does not e this evening。unless常用来引导一个谈及过去的事后的想法，unless从句跟着主句，通常用破折号而不是逗号将它与主句分开。