问题
Do you enjoy traveling by air — No, it’s expensive.
A:is building
B:is being built
C:been built
D:be building;
B:is being built
C:been built
D:be building;
正确答案是：
同类题型
Don’t swim here ,or you may be __________.
Don’t _______ the animals in the zoo. They are very dangerous!
The boy the teachers considered ______was caught _____in the exam, which surprised us very much. [ ]
You should learn English by using it.—What ____useful advice! Thank you very much.
Although I have much housework to do, ______ I still feel happy.