目前我国铁路货车空气制动阀的主要种类有哪些？
参考答案：
目前我国铁路货车空气制动阀主要有3种：GK型三通阀、103型分配阀、120型控制阀。
用所给词的适当形式填空。
1. Sweet and soft music makes customers ( stay) longer.
2. I lie in the bed, feeling quite (relax)after a day's hard work.
3. Laws should be made to protect the (endanger) animals.
4. What do you think of (pollute)?
5.The loud music and hard seats make people in_____(fast).
班主任
