为什么 He has a book.变复数为They have some books.he 变成了they 但是This is his book.变复数为These are his books.为什么his这个所有格不用变成复数their

Question

为什么 He has a book.变复数为They have some books.he 变成了they 但是This is his book.
变复数为These are his books.为什么his这个所有格不用变成复数their

Answer 1

因为he在英语中是第三人称,第三人称一般都要用单数.而they在英语中属于第一人称,又是复数形式,所以要用复数.his在英语中是形容词性的物主代词,与单复数无关