题目内容：

校车问题引起了社会各界的广泛关注。请你根据下面的提示．将下列有关乘坐校车的规定补充完整。（每空词数不限)

Here are the rules we must follow when we take the school bus.

★ Don't1.                           the school bus. or you'll miss it.

★ Please 2.                  in line when you get on or get off the bus.

★ Don’t drop litter. Keep the bus clean and tidy. 

★ Don't talk to the drivers. It is necessary to keep3._________________

★ Don't put your heads or your arms out of the windows.

★ Make sure it is safe to4.                 the street! after you get off the bus.

★ If anything unusual happens, please5.                              .