（1）too, as well和 also用于肯定句和疑问句，too和as well一般放在句末。

而also一般放在句中与动词连用，either用于否定句和否定的疑问句，往往放在句末。

如：He went there,too. 或者

He also went there. 他也去那儿。

He didn't go there,either.

他也没去那儿。

I like you as well.

我也喜欢你。

（2）顺便提一下： as well as用作连词引出比较从句，其义为“和…一样好”。

因此,“He speaks Spanish as well as English．”应译作：“他说西班牙语像说英语一样好。”

练习：

A. Mr. Green can _____speak Chinese well.

B. I haven't heard from him. She hasn't heard from him, ______.

C. I have been to Beijing twice, _____.

D. People in Korea celebrate the Spring Festival _____.

4. ago，before：“之前”

二者意思相似，但用法很不一样。

（1） ago通常和一般过去时态的动词连用，前面是一个表示时间段的词或短语。

如：We started our class about ten minutes ago.

我们大约十分钟前开始上课的。

（2）before通常用来表示在某个时间点之前。

如：We started our class before eight o'clock.

我们八点前开始上课的。(不能说eight o' clock ago)

（3） before可以单独用作状语，而ago则不能这样用。

如：I read about it in a newspaper before.

我以前在一张报纸上看到过这件事。

练习：

A. Everyone should come back _____ five o'clock. No one should be late.

B. "He came back two days ____." means "He came back the day ____ yesterday."