Children develop at their own pace, but there are some common milestones that most 4-year-olds reach. Here are some things a 4-year-old should know according to the search results:

• Language and Communication: A 4-year-old should be able to speak in sentences with four or more words, tell stories, and answer simple questions. They may also use some "bad" words if they have heard them spoken repeatedly.

• Cognitive Skills: A 4-year-old should be able to understand the difference between fantasy and reality, understand time better, count, sort objects by shape and color, and complete age-appropriate puzzles. They may also begin to understand the concepts of "same" and "different".

• Motor Skills: A 4-year-old should be able to run, hop on one foot, catch and throw a ball overhand, walk downstairs alone, and pedal a tricycle. They may also be able to stand on one foot for more than 9 seconds, do a somersault and hop, and walk up and down stairs without help.

• Social and Emotional Skills: A 4-year-old should be able to interact and socialize with others, cooperate with their friends, take turns, and show some problem-solving skills. They may also show a wide range of emotions, such as being sad, angry, happy, or bored.

• Other Skills: A 4-year-old should be able to draw a person with three separate body parts, build a block tower with 10 blocks, and use age-appropriate scissors. They may also understand everyday things like food and money.

Its important to note that every child develops at their own pace, and some may reach these milestones earlier or later than others. Parents can help their childs development by reading with them, answering their questions, teaching them about colors, shapes, and sizes, and giving them choices that are simple and healthy.