outside:1.名词,"外面;外部;外边;外表;外观"

eg:This coat is silk on the outside.

2.形容词,"外面的;从外面来的;外部的"

eg;I'd like to see an outside world.

3.副词,"在外面;外面地;向外面"

eg:The car is waiting outside.

4.介词,"在...外;除了"

eg: He is outside the door.

No one knows about it outside my brother.

out:副词,"向外;在外;出去;出现;发生;问世;完全;消失;到终点;大声地"

eg:Let's go out.

He is out.

The moon is out .

I'm tired out.

My shoes are worn out.

The oil has run out.

Read out ,please.

have to : "不得不＂　（表示客观要求）

eg: The room is too dirty. I have to clean it.

must :　＂必须＂　（表示主观意志）

eg: I must go now. out 副词 一般是指向外 比如 look out 有向外看的意思(当然这个词组还有个小心的意思)

out of 后面加名词 表示在...的外面

outside 副词 一般是在外 比如 I play outside. 我在外面玩

还有 介词 后面加名词 outside his house 在他家外面

形容词 外面的 outside tree 户外的树

名词 在外面 outside is so hot 外面很热