问题 单项选择题

对往复泵产生振动的原因说法不正确的是()。

A、底座松动

B、泵内有气体

C、发生气蚀

D、泵轴与电机轴不在同一中心线

答案

参考答案:C

阅读理解
阅读下面短文,从每题所给的A、B、C、D四个选项中,选出最佳选项.
Fun With Food
This fun e-book is filled
with exercises-photo testy,
word exams, riddle games,
coloring pages and exercises
on learning more about food
Kids Food Science Experiments
Learn more about science
and cooking with these Food
Science Experiments and
instructions for kids.

Food Facts E-Book
  To go with the kids cooking lessons e-book, we've
put our food facts into one e-book. Each part is easy
to print off. You can keep it in the kitchen and teach
kids facts about the food we eat.
  The Food Facts E-Book has
over 60 Pages.                                    

 

Kids Cooking Lessons E-Book
   We've brought all our kids cooking
lessons together into one easy e-book. We
have a unit for each age group .This e-book
is just planned to help you with cooking
experience in the kitchen.
If you'd like our lessons
In e-book from with some
learning exercises and other
things, then this e-book is
for you.
1. Kids can _____ by reading Fun with Food.
A. do science experiments                  
B. get cooking experience,, 
C. cook well in the kitchen                
D. play some riddle games
2. _____ has over sixty pages. 
A. Fun with Food                        
B. Kids Cooking lesson E-Book
C. Food Facts E-Book                    
D. Kids Food .Science Experiments
3. Kids Cooking Lessons E-Book is popular because      
A. there is a unit for each age group    
B there are a lot of photo tests in it
C kids can learn more about science    
D each part is very easy to print off
论述题