According to the definition, education is to educate and cultivate the mental development of the educated in a planned and organized way. Teachers with good knowledge impart their knowledge and skills to students through education. Students gradually form relatively perfect and rational conscious thinking in their study, and their understanding of things is improved from sensory touch to cognitive understanding. Therefore, education is to cultivate talents and improve people's comprehensive quality, and no one will disagree. But education is not only for cultivating talents, but also plays a key role in "screening talents", but many people choose to turn a blind eye. Every parent wants their child to be a phoenix, and they have devoted almost all their efforts to it, not only spending a lot of money, but also spending a lot of time and energy. However, there are always some children who work hard, but their grades are always at the middle level, even at a lower position. Parents tried their best to invite a "gold medal tutor" from an off-campus training institution, but their grades still didn't improve. This situation mostly occurs in primary schools and senior middle schools. With the increase of years of education, there are more and more such students.

Screening is an important function of education. In middle school, the learning content is becoming more and more complicated, and the requirements for students' logical thinking ability, spatial thinking ability and inductive summing-up ability are getting higher and higher, and some students feel more and more difficult. It's not that they don't work hard, that they don't want to do well in their academic performance, but that they really don't have the ability to do it. A series of educational processes let them see the fact that their learning ability is average.