Analysis:

(1) There are too many knowledge points and many questions in senior high school mathematics, which need more time to master.

(2) There are relatively few knowledge points of physical chemistry in high school, but the description of the topic seems to be many words, which makes people feel very difficult, but it is not difficult.

(3) Mathematics, physics and chemistry, 80% of the questions are played with fixed routines. To prepare for the college entrance examination, we should focus on middle and low difficulty topics.