There are over 58, 000 rocky objects in ________ space, about 900 of which could fall down onto________ earth.
| A．the; the | B．不填; the | C．the; 不填 | D．a; the |
—Tom lost his job last week．
—___he is wandering in the street these days．
| A．No doubt | B．No way | C．No wonder | D．No problem |
The witnesses(证人) of the accident said that the lorry _______ very fast at the crossroads when the accident happened.
| A．is traveling | B．had travelled |
| C．was to travel | D．was travelling |
._____ nothing is doing ill.
| A．Do | B．To do | C．Doing | D．Does |
Our monitor talks about Mars as if he ______ a scientist.
| A．is | B．were | C．be | D．had been |
Your floor is dirty. It needs _______.
| A．clean | B．to clean | C．cleaning | D．cleaned |