다음 중 어법상 틀린 문장과 이유가 궁금해요
1.a school is a place at wihich students study.
2.may 14th is the day on which she was born.
3.he traveled to europe which i have been to.
4.2002 is the year when korea hosted the world cup.
5.i like christmas in which all the family members are gathered.