注意：所有题的答案都写在答题卡上面
一、单项选择（10分）
( )1. —______do you exercise ? -- Twice a month.
A. How often B.How many C. How long D. How soon
( )2. ---_________students from Beijing are there in your class？
— Only one.
A. How often B.How many C. How much D. How
( ) 3. It’s very dangerous ________ in the river alone.
A. swim B. swimming C. to swim D. swims
