Question

we have been looking for the boy all the morning but he is nowhere__

a.to see b.seeing c. seen d.to be seen

Answer 1

选择D（出自五高考三年模拟 专题6 动词的时态和语态）
Be to +动词原形 意思是 按计划或安排要做的事

还有8种意思

这是第6种 表示“可以，可能”相当于may ，can
eg：
The news is to be found in the evening paper.
She is nowhere to be found.在哪里也找不到她

Answer 2

选D He is nowhere to be seen 到处都找不到他。

Answer 3

选D。see sb do (doing) sth,sb is to be seen to do sth.

Answer 4

D

Answer 5

a