（）是一个多种功能组合件，用螺栓安装在采空区中部槽侧面的支座上。
A、铲煤板
B、挡煤板
C、联轴器
D、减速器
参考答案：B
下列是美国历史上不同时期使用过的国旗，其中美国独立战争初期使用的是
Directions:
Suppose you are a college student on a school campus or an employee in a company. Recently you noticed that some people never paid attention to the signs on a garbage can that say it is desirable to deal with wastes separately. Now you are going to make a conservation campaign speech at a party. And your speech should include:
1) the present situation,
2) and your suggestions.
Write your letter in no less than 100 words. Write it neatly on ANSWER SHEET 2.
Do not sign your own name at the end of the letter, use "Li Ming" instead.
Do not write the address.
