用括号内所给动词的适当形式填空
It is said that some neighbors saw the boy _______ (walk) towards his home at 10 p.m.
When hiking in the mountains, we had a hard time, _______(sleep) in tents at night.
No one will refuse to join in the game if _______ (invite) .
_______(make) clear that he wouldn't return,the boy rushed out into the dark street.
With many tall trees _______ (surround) it, the old building looked quite quiet.
Not_______(know) what to do next, he came for my aid.
When_______ (watch) their funny performance, we couldn't help             (burst) into laughter.
_______(face) with such a_______ (puzzle) problem, we all felt so_______(puzzle) .
We noticed the little girl_______ (help) the blind man across the street,and then they parted.
The earthquake happened at midnight,_______(kill) countless people.