实验防碰天车时，要由低档至高档逐档试验防碰天车装置。
参考答案：对
用arrangement的适当形式完成句子
1. What do you think of marriage?
2. Who is the of the meeting?
3. We have finished all the for the party.
4. Can I an appointment on Monday?
仓房内安装的换气扇应该叫什么？
