The height and weight standard for 3 years and 4 months old babies: the weight of boys is 10.61-20.64kg and height is 86.3-109.4cm; the weight of girls is 10.23-20.10kg and height is 85.4-108.1cm. when children reach 3 years and 4 months old, the baby’s brain weight is close to the range of adult brain weight, and later the development speed will be slower, the baby The baby is now able to sleep independently and get used to the time of sleeping, going to the toilet, brushing teeth and other work and rest, and has basically been able to stand on his or her own, and at this time the baby can go to kindergarten. Now the child also has a lot of language skills, for example, the child will say a lot of words and use more polite words, the child will also ride a small tricycle, and is also fast, the baby’s observation is more and more careful, and begins to notice the differences between items and make complex classification work. The baby’s thinking begins to transition to concrete image thinking, and can rely on associating remembered things with concrete things, and can use what he or she already knows, has seen, and has heard to think about problems.