John was cleaning the window and Mary was watching TV.
A. at the meantime
B. when
C. meanwhile
D. while
网友回答
A. at the meantime
B. when
(答案→)C. meanwhile
D. while
解析：词义辨析。A.同时，一般谓语句尾 B.当……时候 C. 副词，同时 D.当……时，强调两个动作同时进行。句意：约翰正在擦窗户，同时玛丽正在看电视。While和and不能同时使用，故选C。