It is not difficult to say the second volume, as long as you work hard. A volume 160 exam 100 still needs hard work for science students. If you prefer subjects such as math and physics, choose science. Personally, I feel that liberal arts should not only be good at math, but also not bad at English. Moreover, the normal performance of Chinese is generally inseparable (unless it is particularly good). The first few biology books are not difficult, but the latter ones are a bit difficult. Actually, it depends on which subjects you are mainly good at.