In syntax,what do de mean by immediate constituents of sentence?

The immediate constituents of a sentence are the smaller units that make up the sentence. These constituents can include phrases, clauses, and individual words. In other words, they are the elements that directly combine to form a complete sentence. For example, in the sentence "The cat chased the mouse," the immediate constituents would be "The cat" and "chased the mouse," as these are the smaller units that combine to form the complete sentence.