一、单项选择 (每小题1分，共15分)
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
( ) 1. Tom has _______ ear for music. I think he can be a great musician.
A. a B. an C. / D. the
( ) 2. — What did uncle Paul do five years ago?
— He worked ______ a bus driver.
A. at B. of C. as D. in
( ) 3. — _______ were you late, Betty?
— Because I didn’t know the way to the place.
A. Why B. When C. Who D. How
