Our Earth will be if we go on cutting down millions of trees every year.A. in great dange

问题补充：

Our Earth will be if we go on cutting down millions of trees every year.

A. in great danger

B. danger

C. dangerously

D. out of danger

答案：

(答案→)A. in great danger

B. danger

C. dangerously

D. out of danger

解析：句意：如果我们每年继续砍伐成千上万的树木，我们的地球将陷入极大的危险当中。

in danger 处于危险当中，故选择A。