单项选择题
Jerry seldom came to the laboratory,()
A.did B.didn't C.does D.doesn't
单项选择题 If I had enough money now, I()buy a car.
单项选择题 ()the cause, they were able to propose to a remedy.
单项选择题 Koalas(考拉熊) use a range of sounds to communicate with one another()relatively large distances.