---May I surf the Internet now?
---No, you have finished doing the dishes.
A. unless.
B. if.
C. because.
D. when
网友回答
(答案→)A. unless.
B. if.
C. because.
D. when
解析：考查连词：A.unless除非B.if.如果C.because因为D.when当…时候，根据句子的意思：--我现在可以上网吗？--不，除非你洗完碗。选择A，表示除非相当于if ···not，条件状语从句，故选A