单项选择题
The teacher will not let anyone leave the classroom until the bell （）
A、rings B、rang C、will ring
单项选择题 Jane hasn't finished her homework and I haven't finished mine, （）
单项选择题 I'm busy now, so it will be some time （）I can leave.
单项选择题 Mr. Boffin drove there and （）his car outside the station.
