Question

It is exactly _____we behave _____has changed the world.

1. A.
   which; that
2. B.
   how; that
3. C.
   how; what
4. D.
   what; that

Answer 1

D
句意“恰恰是我们的行为改变了世界的面貌。”去掉it is…that 句子仍然成立