This document discusses aspects of semantic knowledge, utterances, sentences, and propositions. It begins by defining key terms like utterances, sentences, and propositions. Utterances are any spoken language produced by a speaker on a particular occasion, while sentences are abstract strings of words that follow grammatical rules. Propositions describe a state of affairs and can be true or false. The document then compares and contrasts utterances, sentences, and propositions. It provides examples to illustrate the differences between them. Finally, it examines how propositions can be expressed using different sentences. The document aims to explain these fundamental concepts in semantics.