指示代词。
1．this指近处；指示后面要提到的。
例：These are new comers in our class. Those we there are new teachers.
2．that指远处，指示前面提到过的。
例：I want to know this: Has Tom been back long?
What’s that? He said to himself.
3．that/those可在比较句中替代前面提到过的相同名词，避免重复。
例：The weather in Beijing is better than that in Tianjin.
The cars produced in this factory is more than those in that one.
4. that “那么”
He is not that bad.