[질문] I think running as fast as a cheetah is impossible.왜가목적어it으로고쳐질수있죠

이문장에서 running as fast as a cheetah 이부분을 it 으로 바꿀수있는데요 그러니까 I think it is important to run as fast as a cheetah 로바꿀수있습니다