1.that:比較句中替代詞,不可數(shù)名詞that替
2.it:替代若系本身物,it 代單數(shù) they 代復數(shù)
指代動物、物品,可以直接用于句中.
it is hers/they are theirs
指代前面的一句話等,放在前面一句話之后緊接著的句子中,做主語用
3.有的時候通用：that/it is great!
4.one 和ones 指代前面已經(jīng)說過的物品,放在前面一句話之后緊接著的句子中,做賓語用.one 指代單數(shù)物品,ones 指代復數(shù)物品
one泛指或者指代前句的each已經(jīng)說明是單數(shù)形式
The apples here are very small,this is the biggest one.
ones (those后+名詞復數(shù)）
girls in this class are beautiful,those ones are the hottest!
5.the one(特指,后面為定語從句)