问题 问答题 简答题

蒸发性不好和太好的汽油,在使用中各有什么缺点和可能产生的问题?

答案

参考答案:

蒸发性过强的汽油在炎热夏季以及大气压力较低的高原和高山地区使用时,容易使发动机的供油系统产生“气阻”,甚至发生供油中断。另外,在储存和运输过程中的蒸发损失也会增加;蒸发性若的汽油,难以形成良好的混合气,这样不仅会造成发动机启动困难,加速缓慢,而且未气化的悬浮油粒还会使发动机工作不稳定,油耗上升。如果未燃尽的油粒附着在气缸壁上,还会破坏润滑油膜,甚至窜入曲轴箱稀释润滑油,从而使发动机润滑遭破坏,造成机件磨损增大。

阅读理解

Maybe you are an average student. ___小题1:__ This is not necessarily so, however. Anyone can become a better student if he or she wants to. Here’s how.

Plan your time carefully. When planning your work, you should make a list of things that you have to do. After making this list, you should make a schedule of your time. First your time for eating, sleeping, dressing, etc. Then decide a good, regular time for studying. ___小题2:__ A weekly schedule may not solve all your problems, but it will force you to realize what is happening to your time.

Make good use of your time in class. ___小题3:___ Listening carefully in class means less work later. Taking notes will help you remember what the teacher says.

Study regularly. When you get home from school, go over your notes; look at the important points that your teacher is going to discuss the next day, read that material. __小题4:____ If you do these things regularly, the material will become more meaningful, and you’ll remember it longer.

Develop a good attitude towards tests. The purpose of a test is to show what you have learned about a subject. They help you remember your new knowledge. The world won’t end if you don’t pass a test, so don’t be over worried.

__小题5:___ You will probably discover them after you have tried these.

A.There are other methods that might help you with your studying.

B.Don’t forget to set aside enough time for relaxation.

C.Take advantage of class time to listen to everything the teacher says.

D.No one can become a top student unless he or she works hard.E. You probably think you will never be a top student.

F. Make full use of class time to take notes of what the teacher says in class.

G. This will help you understand the next class.

判断题