搜题请搜索小程序“爱下问搜题”
问题 问答题 简答题

刮板输送机挡煤板的作用？

答案

参考答案：

增加溜槽装运货载的断面积，提高运输能力，并防止煤炭溢出抛撒到采空区，还利用它来敷设和保护电缆、油管、水管等管线。

单项选择题

请根据下面短文回答下列问题：
Whenever you go on holiday abroad you may see different kinds of animals. Many of them will not be well looked after and you might feel sad about this. Here are a few suggestions on how you can help.

Homeless Animals


In many countries you’ll find homeless cats and dogs around your hotel. Please don’t give food to them—this only encourage more homeless animals to your hotel and the animals then come to tourists for food. The food stops once the holiday season is over and then animal welfare organisations (动物福利组织) in the city have to pick up the animals. These organisations are often very small and need money to keep going. To help them out, why not give some canned or dried food or give them money. To find an animal welfare organisation, try the phone book or ask the hotel manager.

Animals at a Market


Markets are a fact of life in many countries and you may very well see animals kept in cages which are far too small and left sitting in the hot sun. You could write to a newspaper telling them how much better it would look to visitors if people in the market could stop that practice.

What is this text about
[A] Animal welfare.
[B] Lost cats and dogs.
[C] An animal-friendly tourist.
查看答案
选择题

已知甲，乙两组数据的平均数相等，若甲组数据的方差S甲2=0.055，乙组数据的方差S乙2=0.105，则（　　）

A．甲组数据波动比较大

B．乙组数据波动比较大

C．两组数据的波动一样大

D．两组数据的数据波动不能比较
查看答案