that 是副词,意思是“那样,那么,如此,这样”,表示程度
1.用作程度状语,如：
I can't walk that far.我无法走那么远.
2.修饰副词,如：
I've done only that much.我所做的就这么多.
3.修饰形容词,如：
I was that angry I could have hit him.我十分生气,简直想揍他.
It isn't all that cold.天气没有 冷到那种程度.