问题
Scientists are working hard to make _______ possible for people to live on Mars in the future.
A:it
B:that
C:this
D:one
B:that
C:this
D:one
正确答案是：
同类题型
They are getting ready ____ fly ____ England ____their holiday. [ ]
Why do you like living here？ — Because it’s quite quiet. There are cars on the street.
How about putting some pictures into the report?—________．A picture is worth a thousand words．
Hi，dear! I’m phoning to_________ you that it is time to take your medicine． —Thank you．