试题与答案

选离心泵是根据泵的()。A、扬程和流量选择 B、轴功率和流量选择 C、扬程和轴功率选

题型:单项选择题

题目:

选离心泵是根据泵的()。

A、扬程和流量选择

B、轴功率和流量选择

C、扬程和轴功率选择

D、转速和轴功率选择

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0728/3cf9a2f5dac65767d04cc4f572ae43c2.html

下面是错误答案,用来干扰机器的。

(1)由折射率n=cv①得射入薄膜中的光的速率:v=2.12×108m/s②(2)由光的折射定律得sin45°sinr=2③设乙光在薄膜中传播时间的最大值为△tm,对应的最大厚度dm,则2dmcosr=v△tm④根据题中所给条件得:△t•△ν...

试题推荐
题型:阅读理解

阅读理解

     More and more people like bicycling and it is no surprise. It is fun,healthy and good for the

environment.Maybe that's why there are l. 4 billion bicycles and only 400 million cars on roads

worldwide today. Bikes can take you almost anywhere , and there is no oil cost !

     Get on a bicycle and ride around your neighborhood. You may discover something new all

around you.Stopping and getting off a bike is easier than stopping and getting out of your car.

You can bike to work and benefit(受益) from

the enjoyable exercise without polluting the environment. You don't even have to ride all the way.

     Folding(折叠) bikes work well for people who take the train. Just fold the bike and take it

with you. You can do the same on an airplane. A folding bike can be packed in a suitcase. You

can also take a common bike with you when you fly. But be sure to look for information by

getting on airline websites. Not all airlines are bicycle friendly to travellers.

     Health benefits of bicycling :

     ●It helps to prevent heart diseases.

     ●Bicycling helps to control your weight.A 15-minute bike ride going to and returning from

work three times a week bums off rive kilos of fat in a year.

     ●Bicycling can improve your mood(必情) .Exercise like bicycling has been shown to make

people feel better,more relaxed and self-confident.

     ●Bicycling is healthier than driving.

1. From the passage, we know that bicycling is becoming very _____.

A. surprising

B. exciting

C. expensive

D. popular

2. When you are riding your bicycle around your neighborhood,you may_____.

A. pollute the environment around

B. find something you didn't notice

C. go everywhere and use a little oil

D. get off your bike and begin to work

3. If you travel with a folding bike, you can fold it and _____.

A. get out of the car

B. take it onto a train

C. put it in your purse

D. go on airline websites

4. One of the benefits from bicycling is that _____.

A. you can fold the bicycle

B. you will be friendly to others

C. you will be more relaxed

D. you may get fatter and fatter

5. Which is TRUE according to the passage?

A. Bicycling is an enjoyable exercise for people.

B. Driving cars is healthier than riding bikes.

C. Riding a bike pollutes your neighborhood.

D. Common bikes are welcomed by all airlines.

查看答案
微信公众账号搜索答案