강조용법으로 쓰인것을 고르시오.

1. what did you do last weekend?
2. he does not know her address.
3. i did want to know the answer.
4. he did a lot of work with his team.
5. seldom did i meet her.

각각 무슨용법으로 쓰인지알려주시구요...5번은 해석도잘안되요..^^;;