— __________ have you been to Hong Kong on business?
— Once in a month.
| A．How old | B．How often |
| C．How soon | D．How long |
Sam wants to be _________ actor.
A. a B. the C. an
—Dad,________ is my Mp4?
—It’s in your desk.
A. where B. what C. whose
Mary often has eggs and bread _________ breakfast.
A. with B. for C. on
What’s the best present you have ever ________?
A. received B. receives C. receiving
Do you know the girl _________ is singing in the classroom?
A. when B. who C. which