代词是代替名词、形容词和数词的词。按其意义、特征及其在句中的作用分为：人称代词、物主代词、指示代词、反身代词、相互代词、疑问代词、不定代词和关系代词等。
一. 人称代词 1.人称代词的人称、数和格，如下表所示。
2.人称代词有主格和宾格之分。通常主格作主语，宾格作宾语。如： I like table tennis. (作主语) Do you know him?(作宾语) 3.人称代词还可作表语。作表语时用宾格。如： ---Whos is knocking at the door? ---It s me. 4.人称代词在than之后与其他人或事物进行比较时，用主格和宾格都可以。如： He is older than me. He is older than I am. 二. 物主代词 1.表示所有关系的代词叫物主代词。物主代词分形容词性物主代词和名词性 物主代词，如下表所示。
2. 形容词性物主代词的作用相当于形容词，可在句中作定语。例如： Our teacher is coming to see us. This is her pencil-box. 3. 名词性物主代词的作用相当于名词，在句中可用作主语、宾语和表语。 Our school is here, and theirs is there.(作主语) --- Is this English-book yours? (作表语) --- No. Mine is in my bag. I ve already finished my homework. Have you finished yours? (作宾语) 三. 指示代词 指示代词包括：this，that，these，those。 1. this和these一般用来指在时间或空间上较近的事物或人，that和those 则指时间和空间上较远的事物或人，例如： This is a pen and that is a pencil. We are busy these days. In those days the workers had a hard time.