Our teacher often keeps us ______ classroom every day, so we must keep our classroom_______.
| A．clean, clean | B．cleaning, cleaning |
| C．cleaning, clean | D．clean, cleaning |
What method can you think of _________ with these broken computers?
| A．dealing | B．deal | C．deals | D．to deal |
Scientists are trying their best to_______ ways to treat the terrible disease caused by Ebola(埃博拉）．
| A．come up with | B．look forward to |
| C．talk about | D．give up |
—What shall we do this Saturday?
— it rains, we’ll have a picnic in Century Park.
| A．If | B．Unless | C．Because | D．When |
It's a pity that I didn't think of ringing you .
| A．earlier | B．earliest | C．early | D．the earliest |
To remember things accurately, we don't allow other thoughts our mind.
| A．enter | B．to enter | C．entering | D．entered |