1, intelligent development characteristics ① large movements: the baby’s ability to roll over further development, can be more skilled from the supine position to turn to the side, and then turn to the prone part; can sit for a short while, gradually can sit with the upper body leaning forward; prone position can raise the head and turn the head to look around, supine position can raise both feet and stirrup kick. ② Fine motor: At this time, they can touch things with their hands, and shake and knock things. ③ Language development: The baby’s language skills further improve, and he/she can understand words and tones of praise or criticism, and make monosyllabic sounds. ④ Cognitive ability: He will look at himself in the mirror and smile happily, play hide-and-seek, and is interested in things related to himself such as milk bottles and spoons. ⑤ Self-care ability: Can hold a bottle and wants to drink milk. ⑥ Social interaction: they can recognize people, recognize their mother, distinguish their mother’s voice, and feel happy and shout at their mother’s voice; they can distinguish between acquaintances and strangers, and like to approach acquaintances but reject strangers; they will turn their heads and look for their mother and father when they leave. 2. Ability training ① Sitting: after the baby can roll over freely, you can try to hold the baby to sit for a while, then gradually let the baby lean on the sofa or small chair, play with toys, and gradually reduce the back support, train the baby’s ability to sit alone, pay attention to the safety of the training. ② Upright jumping: for 5-month-old babies, parents sit, hold the baby’s armpits with both hands and let the baby’s feet jump on the parents’ legs, practice for 1 minute each time, 1-2 times a day. ③ Rotation: Parents hold the baby in the beautiful music, rotate the body 360 degrees, and can move the body up and down, so as to train the ability to change position and maintain balance. 3, cognition, language and communication (1) cognition: ① let the baby play happily, choose the right toys, and control the speed of play, to guide the baby’s own initiative to cooperate, wait patiently for the baby to complete the active action. Such as the initiative to take toys, parents do not take the initiative to stuff in the baby’s hand because of anxiety. ②To train the baby’s ability to grasp objects accurately, such as putting some toys of different sizes and shapes in front of the baby, let the baby take the toy they want with their own efforts, and exercise their brain-eye-hand coordination. ③Let your baby learn to play with toys by himself, let him hold the toy to see, touch, shake, listen, parents can tease and talk at this time, when the baby succeeds, kiss the baby to show encouragement. ④Let the baby sit on the parent’s lap or hold the baby, and the baby play hide-and-seek game, once the baby will find a very happy smile, you can hide the toy and then suddenly take out, or adults hide and then suddenly appear in front of the baby, etc., can also be a handkerchief covering the baby’s face or eyes. ⑤ Use a toy that can be rolled, preferably with sound, to attract the baby’s eyes to follow the toy, and then let the toy fall suddenly to guide the baby to find the disappearing toy, so as to develop the baby’s observation skills. ⑥Tie a red or green or blue ball of string with a belt and roll the ball from near to far to a place where the baby can’t hold it, then pull the ball back. Let the baby watch it a few times, and then let him or her imitate the parent’s actions to train eye-hand coordination. (7) Place two ping pong balls or small toys in front of the baby, and after the baby reaches out and grabs one, the parent trains the baby to use the other hand to grab the other one. Repeat this to practice the baby’s ability to grasp with both hands. (2) Language: 5 months old baby, the perception of speech is clearer, more active pronunciation, will take the initiative to issue some unclear syllables, at this time, parents can consciously baby to make some sounds, guide the baby to imitate the sound issued, especially the frequent contact with things more repeatedly said. At the same time also consciously tell the baby his own name, repeated training, so that it has a response when parents call his name. (3) Life and interaction: ① Continue to face the mirror with your baby to learn, you can interact with the person in the mirror, teach your baby to observe his own look in the mirror, and teach your baby to recognize the eyes, nose, mouth, etc. ②Through the baby’s hand grasp training, you can let the baby hold the food to eat by themselves, such as giving the baby some good to hold, easy to digest small cookies, training the baby to hold the cookies to feed themselves into their mouths. ③5 months old baby will gradually recognize people, you can hold the baby and children or adults to play together, training the baby to recognize people, while telling the baby to recognize the person how to call. ④Sign of abnormality: 5 months old baby, if you can’t roll over, it is recommended to strengthen the training at the same time to find a professional doctor to check.