Отметьте верно составленное предложение: 1. My sister, who is twenty years

Отметьте правильно составленное предложение:
1. My sister, who is twenty years old, is a student. My sister, which is twenty years old, is a student.
2. He worked hard this month. He has worked hard this month.
3. What a nice man! What nice man!
4. Are there some chairs in the room? Are there any chairs in the room?
5. They walked faster. They walked more fast.