How pleasant the picture is to _________!
| A．be looked at | B．being looked at | C．looking at | D．look at |
30．How long do you think it will be _____ we can find a new water source?
| A．after | B．before | C．when | D．Since |
29．High up in the mountains _____ a quiet small village, with only 20 households．
| A．surrounds | B．locates | C．lies | D．Lays |
28．A heavy snow promises a good harvest, _____ is often the case．
| A．where | B．as | C．that | D．What |
27．After his wife died, he kept himself _____ from other people and the outside world,
| A．set off | B．cut off | C．put off | D．taken off |
26．— Why is little Jimmy so naughty today?
— He is bored, so he _____ a little silly．
| A．will be | B．is being | C．had been | D．would be |