问题
选择题
--Shall Mary come and play computer games?
--No,__________ she has finished her homework.
A．when
B．if
C．unless
D．once
答案
答案：C
本题只要理解了句意就能很容易地选出unless。句意为：“玛丽要来打电脑游戏吗?”“不，除非她完成了作业。”
搜题请搜索小程序“爱下问搜题”