一间办公室如果有三人以上，应注意办公桌不要（）摆设，以免影响思考。
A.靠墙
B.当中
C.面对面
D.朝向门口
参考答案：C
I have no idea whether he has sisters, and if he does, _____？[ ]
A. how many sisters does he have
B. he has how many sisters
C. how many he has sisters
D. how many sisters he has
二色镜一端的透镜应焦正在：（）.
A.前端的窗口
B.窗口外的宝石
C.冰洲石棱镜的前端
D.冰洲石的后端
