副词在句中可作状语，表语，补语，定语。

He works hard. （作状语）
他工作努力。

You speak English very well. （作状语）
你英语讲得相当好。

Does she stay home? （作表语）
她呆在家吗?

[she stay home是主系表结构，stay 此处是[linking verb 连系动词]， home 是[adv.]，作stay的表语]

[PS: 至于she stays at home...此处stay是实义动词，整个句子是主谓结构，at home是介词短语做地点状语]

Let's be out. （作表语）
让我们出去吧。

Food here is hard to get. （here作定语，hard作状语）
这儿很难弄到食物。

Let him out!（作补语）
让他出去！

.修饰名词的副词放在被修饰词之后

a. The villagers there are busy getting in wheat.

位置

1) be动词、助动词或情态动词之后，实义动词之前。 如果实义动词后有宾语，则放于宾语之后。

I am also Bush.
我也是布什。

I can also do that.
我也可以这样做。

I also want to play that games.
我也想玩这游戏。

I get up early in the morning every day.
每一天的早晨我都起得很早。

She didn't drink water enough.
她没有喝足够的水 。

We can go to this school freely.
我们可以免费到这家学校学习。

They left a life hardly then.
当时他们的生活很艰难。

I have seen this film twice with my friends.
这部电影我和朋友看过两次。

2) 副词修饰形容词，副词时，一般放在被修饰词之前，但enough除外。

It's rather easy， I can do it.
这很容易，我能做到。

He did it quite well.
他做得相当好。

3) 频度副词可放在实义动词的前面，情态动词和助动词的后面。

I often help him these days.
这些日子我经常帮助他。

I always remember the day when I first came to this school.
我常常记得我第一次来学校的那一天。

You mustn't always help me.
你不能老是帮助我。

We usually go shopping once a week.
我们通常一周买一次东西。

The new students don't always go to dance.
新学生并不时常去跳舞。