读一读，选择正确的单词填空。
【小题1】Welcome ___________(to/in) our school.
【小题2】Our library is __________(on/in) the first floor.
【小题3】This is the __________(teachers/teachers' ) office.
【小题4】—How many _________(student/students) are there in your class? —Forty-two.
【小题5】—_________(Is/Are) that the computer room? —No, it isn't.
【小题6】—_________(Are/Do) you have a computer room?  —Yes, we do.