采煤机选型原则有（）。A、使用、检修、维护方便B、技术性能良好_爱下问搜题

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问题多项选择题

采煤机选型原则有（）。

A、使用、检修、维护方便

B、技术性能良好

C、价格低廉

D、采煤机合理的参数

E、满足与刮板输送机和液压支架的匹配

答案

参考答案：A, B, D, E

补全对话，情景问答

给下列问句选择恰当答语。

( ) 1. What is it doing?
( ) 2. When are you going?
( ) 3. Which season do you like best?
( ) 4. How does your cousin go to work?
( ) 5. Whose backpack is this?

A. I like fall best.
B. It's Lucy's.
C. It's eating bananas.
D. He goes to work by subway.
E. We're going next Sunday.

填空题

按土的压缩系数确定土的压缩性时，如果定义某土为高压缩性，则该土的压缩系数a_1-2应大于______MPa^-1。