The level of large class education and small class education in Washington University is uneven, so there is a saying that "meeting a good professor at the beginning of the semester is half the battle". Some professors have passion and level, so that students can listen carefully even in nave class with more than 100 people; Although there are only thirty or fifty students in some small classes, it is urgent for professors not to teach them. Generally, the specialized courses of level 300 will be transferred to small classes, and the basic courses of level 100 are all large classes, with 100~500 students. The introduction to architecture I am taking now is a large class of 500 people. It is impossible for a professor to take care of every student, so self-study is also a very important part of college life.