The windows , so you need not wash it again.
A. is washed
B. was washed
C. have been washed
D. will be washed
网友回答
A. is washed
B. was washed
(答案→)C. have been washed
D. will be washed
解析：考查谓语动词。The windows作主语谓语应用被动语态，根据语境you need not wash it again “不必洗”所以应用完成时的被动语态选C