第 一节  单项选择（共15小题；每小题1分，满分15分）

       21．The number of people who        English as a foreign language        more than 750 million.

A. learns; is          B. learn; are       C. learns; are        D. learn; is

22．When you finish, please put the book back             it was.

    A. where           B. at which        C. the place        D. the place that

23．____home, the light in the room was still on.

A. Arriving  B. On arriving  C. When arriving  D. When I arrived