Ⅰ. 单项选择 (共25小题，每小题1分, 共25分)
从每小题所给的四个选项中选出能够完成或回答这一小题的正确答案。
1. —Mark, please don’t play basketball on the road. It’s very dangerous.
—_________. I am going home at once.
A. Have a great time B. Sorry, I won’t do that C. I’d like to D. OK, with pleasure
2. You are doing great! I’ve never had ______ answer before.
A. better B. best C. a better D. the best
3. We didn’t start our discussion ________ everybody arrived.
A. since B. if C. because D. until
