밑줄 친 분분의 쓰임이 나머지와 다른 하나는?

1.) It is too windy and cold outside.

2.) It is impossible to review the plan.

3.) It's necessary to take care of the poor animals.

4.) It is very hard to break an old bad habit.

5.) It might be better to give up before too late.

밑줄 친 부분이 문장의 실제 주어가 아닌 것은?

1.) It's not easy to jump that high.

2.) It is difficult to learn foreign languages.

3.) It is impossible to make her laugh.

4.) It is about five minutes' walk to the subway station.

5.) It's necessary to check everything once again.