1, doing active thinking for a long time, the brain is easy to get tired, and gradually the brain can't keep up.

2, there are always some problems that are more troublesome, which are easy to make people upset and then feel tired.

3, the method of doing the problem is stupid, which leads to a waste of time and energy.

4, the individual's own brain power is not good.

In view of this situation, I would like to make some suggestions:

1, yesterday for two hours in a row, you can go to a ventilated place to get some air and reduce fatigue from afar.

2. Don't engage in sea tactics, but do targeted topics that cover a wide range of knowledge points and are representative.

3, learn to extrapolate, some topics are very similar, don't solve them all in a period of time, do it again every once in a while, which is equivalent to reviewing and strengthening memory. It can also reduce boredom.

4. Learn to plan your time. Don't study a subject for hours on end, but do it.

Regarding sleep, I suggest you go to bed before 0 o'clock and get up at 6 o'clock in the morning to form a habit. This will ensure that you have enough energy the next day, which is good for your health.