人称代词的主格(I you he she it we you they)作主语(如:I like English.);宾格作宾语或表语(Give me a book.Who is it?It's me.).形容词性物主代词(my your his her its our their)作定语(This is my book.);名词性物主代词(mine yours his hers its ours theirs)相当于形容词性物主代词+一个名词,作主语、宾语或表语(如:Whose book is this?It's mine.(在此mine=my book).