nothing but和merely、only都有“只不过、只是”的意思,它们有什么区别呢?

nothing but：除了…以外什么也没有；只有，不过，不外

merely ['mi?li]

adv.

1. 仅仅；只；不过

2. [废语]纯粹地；绝对地；完全

merely ['mi?li]

adv. and nothing more

I was merely asking

only ['?unli]

adv.

1. 只有，惟有

2. 正好，恰好

3. 才，刚

4. 反而；结果却；不料

5. 作为惟一

adj.

1. 仅有的；(同类中)较少的

2. 惟一的；(子女)独生的

3. 最好的，独一无二的

conj.

1. [有时与 that 连用][主方言]要不是，若非：

I would have made a big mistake only you advised.要不是听了你的劝告，我可犯大错误了。

2. [口语]可是，不过：

I want to go with you, only I havn't got time.

我愿意和你去，可我没有时间。

only ['?unli] adj.

1. being the only one; single and isolated from others

an only child

2. exclusive of anyone or anything else

I'll have this car and this car only

adv.

1. and nothing more

he was only a child

2. without any others being included or involved

a privilege granted only to him

3. with nevertheless the final result

He arrived only to find his wife dead We won only to lose again in the next round

4. in the final outcome

These news will only make you more upset

5. except that

It was the same story only this time she came out better

6. never except when

call me only if your cold gets worse

7. as recently as

I spoke to him only an hour ago

要辨析异同，最好看看基本用法，特别是英语解释。

从以上基本用法可知：

only 词性最多，意义最丰富。当它作副词时，可以和merely通用；但作其它词性时，则不能通用。

nothing but:作副词时，经常连在一起使用，这是一般也可以与其他两个互换；但是，当做连词用时，它还可以分开来使用，两次中间需要加其他词 ，此时不能与另外两词互换。例如：

We have nothing here but some potatoes.我们在这里只有土豆（可吃或提供）。

祝你学习进步，时时开心！O(∩_∩)O~~