In layman's terms: stage fright.

1 It is very common for you, mainly to get through your own ideological work. For example, I set a time when I am doing the paper and regard it as an exam. (Overcome nervousness)

You said you studied well. Have you considered the efficiency of doing the problem? If you work on the same topic for half a day, do you still have enough time to go to the examination room?

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