四、注意that which的用法
that which中的which為關系代詞，用以引導定語從句，其意為“……的事或物”，這是一種比較正式的用法，它通常可以用what代之。如：
That which (=What) many people say is not always true. 很多人說的話并不表示一定是真的。
That which (=What) I say and do is my own affair. 我說什么做什么是我自己的事。
They say the only real knowledge is that which can be measured. 據說唯一真實的知識是可以檢驗的知識。
The picture tries to convey an attitude towards life.
It happens in life that...
Such a situation seems fairly common in our society

五、注意that的替代詞用法
指示代詞that有時可用作替代詞，用來代表前已提過的事物，以避免重復，如：
A grandparent's job is easier than that of a parent. 祖父母的任務比父母的任務要輕松一些。
A dog's intelligence is much greater than that of a cat. 狗的智慧比貓的高得多。
The dialect in one town may he quite different from that of the next town. 一個城鎮的方言可能與另一個城鎮很不相同。
The weather of Beijing is just as cold as that of Lanzhou, but colder than that of Shanghai. 北京的氣候和蘭州一樣冷，但比上海冷。

六、注意that, this用作副詞
指示代詞有時可用作副詞，其用法與so相似。如：
It isn't all that cold. 還沒冷到那種程度。
It's about this high. 約摸這樣高。
Is it this hot every day? 每天都這樣熱嗎?
I didn't think it would be this easy. 我沒想到會這樣容易。
I didn't realize she was that ill. 我沒想到她病得那么重。
The book is about this thick. 那本書大約有這么厚。
When you pay that much for a meal you expect the best. 一頓飯花那么多錢是想吃到最好的東西。