问题 选择题

He promised to help me and then_________.

A.back out

B.backed out

C.backed of

D.backed on

答案

答案:B

词义辨析。back out不遵守诺言;backed of在……后边;backed on背靠。句意:他许诺了帮助我,然后又反悔了。根据句子谓语promised,所以用一般过去时,选B。

单项选择题
单项选择题 A1/A2型题