3.The windows of the room_____once a week.
A.has been cleaned B.is cleaned
C.are cleaned
D. are cleaning
出自:大学英语1

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
向右拖动滑块