If you don't want to spend money, then push-ups, sit-ups, flat support and squats are almost enough. They don't cost money and take up space, and everyone can do simple actions. And there is no need to worry about affecting neighbors, and there is no requirement for time. If you are sleepy in the middle of the night, you can do some refreshing exercises, and the effect is still good. If you practice hard, maybe you can get some muscle blocks. Is this not good?
If conditions permit a little, you can buy some small fitness equipment, such as small dumbbells, arms, tensioners, abdominal wheels, handles and so on. Except dumbbells, it is estimated that 100 is enough. The advantages of these equipment are no land occupation, unlimited time, no noise, no disturbance to the people and good exercise effect!
Of course, if you want to take the postgraduate entrance examination, it must be academic, so these things are only used in the gap between studies, and their main function may be to relax and refresh. But if you can spare a relatively fixed time, such as every night or morning, that is the best. After all, exercise, like study, is not a day's work, and only long-term persistence can have an effect.
I think those who can aspire to take the postgraduate entrance examination are not ordinary people. They must have confidence in their abilities and become experts in learning. Their IQ is definitely not low, and then they have the idea of exercising. It is really hard to get! As long as you can persevere, you will make a difference. If you can raise your pen to secure the world, if you can mount a horse, you are the pillar of the country!