可以用作連詞，表示“因此，所以”。

例：I heard some noise outside, so I went out of the room to see why.

so that作為連詞詞組，表示 “以便，為了”。

例：The vase is put high on the table, so that it won't be broken.

可以用作形容詞，表示“是這樣的，是真的”。

例：The newspapers claim she killed him in self defence but that just isn't so.

可以用作副詞，表示——

1）“如此，這么”結(jié)構(gòu)為：so+adj./adv

例：She was so tired that she fell asleep very fast.

表示此意思時(shí)，還可以用：so+adj.+a/an+n.

例：It is so good a movie that everyone who saw it praises it very much.

2）“如此，如是”，用于表示已經(jīng)提到的想法，建議或情況等

例：“Will I need my umbrella?”

“I think so.”

3）“也是，也一樣”結(jié)構(gòu)為so+助動(dòng)詞/情態(tài)動(dòng)詞/be動(dòng)詞+主語(yǔ)

例：Tony takes exercise every day and so does his younger brother.

注意否定句應(yīng)把so改為neither/nor，結(jié)構(gòu)為neither/nor+助動(dòng)詞/情態(tài)動(dòng)詞/be動(dòng)詞+主語(yǔ)

例：Jenny has never been late for class.Neither/Nor her younger brother.

4）“確實(shí)是這樣”，表示對(duì)前面陳述事實(shí)的強(qiáng)調(diào)，結(jié)構(gòu)為so+主語(yǔ)+助動(dòng)詞/情態(tài)動(dòng)詞/be動(dòng)詞

例：Tony works very hard at all the subjects.So he does.

5）“似乎，那么”，表示驚訝、不同意或者嘲諷

例：So you think you've got troubles?

常見(jiàn)結(jié)構(gòu)：and so on/and so forth：等等；so as to（do）：以便；so that+從句：以便

例：We eat different vegetables， such as tomato，potato，celery，and so on.

They got up early so as to catch the first bus.

They got up so early that they could catch the first bus.