问题

People ____ more and more useful things to protect the earth since Earth Day was started.

A:did
B:were doing
C:will do
D:have done;

正确答案是：

同类题型

Which sentence is wrong?

s a _____ in our office that when it’s somebody’s birthday, they bring in a cake for us all to share.

More and more people come to visit Mount Huangshan.—That’s true. It has become the of Anhui.

________ there any American teachers inyour school —________ .

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