2. Will vomit small tongue. Although we teach our children not to spit out their tongues at people when they grow up, this is uncivilized behavior, but for a half-year-old baby, this is a smart performance.
3. Be able to concentrate. Most babies are actually sleepy, get enough rest and are generally energetic, and like to communicate with people all the time. If you find that the baby is staring at something without crying or making trouble, it also means that the baby is really smart.