The children were running, laughing, and playing.

Meaning: This sentence also describes what the children were doing, but it uses more specific language to indicate that they were in the middle of these activities. It gives us a sense of the children's energy and enthusiasm.

Choice of Words: The children is a more specific way to refer to the children in the sentence. Were is the past tense of the verb to be, which is used to describe a state or condition. Running, laughing, and playing are all present participles, which are verb forms that describe an ongoing action or state.