What is the most stressful part of school？It is probably the jye.ai.Exams can put us under a lot of pressure But some students do better under pressure，while others do not.So，why do some students perform better under stress？It all comes from dopamine（多巴胺）.Dopamine is a chemical in our body that sends messages to the brain.It has many important roles-it makes a difference to our memory，attention and how we learn.Our brains work best when there is a balance（平衡）of dopamine--not too much or to little.
   Our brains control dopamine in two ways.It either takes out dopamine quickly or gradually.Exam success is related to how fast dopamine goes back to an even balance，according to a new research.What will happen when we take an exam？If you become stressed，your brain will start to overload on dopamine.It is like a cup with too much water.The quicker you are able to go back to an even balance of dopamine，the quicker you can focus.It helps you perform better on a test.
   Scientists found that during a test，people who slowly got back to an even balance of dopamine scored eight percent lower.That's the difference between a good grade and a bad grade.But don't fear-there is good news for every student.The study also found that the more practice you get，the less stressed you will be.
（1）According to the passage，whether students can do well under pressure in the exam depends on

A

A

.
A.dopamine
B.practice
C.teachers' help
D.hard work
（2）Dopamine has an influence on us in some ways except

D

D

.
A.memory
B.attention
C.the way to learn
D.balance
（3）The underlined phrase "is related to" probably means

A

A

.
A.has to do with
B has nothing to do with
C.gets on with
D.deals with
（4）What can be inferred（推断）from the passage？

C

C

A.The writer is pretty good at schoolwork
B.The more dopamine there is，the better our brain works.
C.Enough practice makes students less stressed.
D.The more stressed we are，the less dopamine our brains have.