1. that 作指示代词：Thatis my book. 那是我的书。

2. that 作指示形容词：We haven't found any solution to deal withthatproblem yet. 我们仍未找到解决问题的办法。

3. that作关系代词引导定语从句：This is the sort of thingthatJeremy loves. 这是杰里米喜欢的东西。

4. that 作连词：that 可以作连词引导各种名词性从句，包括宾语从句、主语从句、同位语从句和表语从句。

1) that 作连词引导宾语从句：They have recommendedthatthe site be closed and repaired. 他们建议将该处关闭并进行维修。

2) that 作连词引导主语从句：Thatyou will win the medal seems unlikely. 你想获得奖牌看起来是不可能的。

3) that 作连词引导同位语从句：The ideathatmodern art can only be seen in museums is mistaken. 现代艺术只能在博物馆才能见到的想法是错误的。

4) that 作连词引导表语从句：One problem isthatI don't look any different from other people. 有一个问题是我看起来和其它人没有任何不同。

5. that作副词：that和 this 都可以作副词，用于修饰形容词或修饰另一个副词，表示“这么，那么，如此，这般”的意思，如:It's aboutthatlong. 它大约有那么长。