Solid geometry in senior high school is not difficult, but some questions require high spatial thinking ability. According to my personal learning experience in high school, the problems of solid geometry training at ordinary times should be more difficult than the college entrance examination, and you said, "I can do it casually, and I do the college entrance examination questions" because the college entrance examination has low requirements for solid geometry, which are generally medium, such as series, conic curve and derivative, which are relatively more demanding and sometimes can be done. ......