only

only, single, sole, unique, alone

形容词 only:

1. being the only one; single and isolated from others
   同义词：lone, lonesome, sole, solitary
2. exclusive of anyone or anything else
   同义词：alone

副词 only:

1. and nothing more
   同义词：merely, simply, just, but
2. without any others being included or involved
   同义词：entirely, exclusively, solely, alone
3. with nevertheless the final result
4. in the final outcome
5. except that
6. never except when
   同义词：only if, only when
7. as recently as

1. Enjoy the disco you're only young once.
   尽情跳起迪斯科－－须知青春只一度。
2. I shall be only too pleased to get home.
   我要回到家里就非常高兴。
3. The book is likely to be useful, only it's rather expensive.
   这本书可能有用，只是相当贵。
4. He is the only person for the position.
   他是担任此职位的最佳人选。
5. He speaks not only English but also French.
   他不但会说英语，而且还会说法语。
6. I saw him only yesterday.
   我昨天才见到他。

on.ly

adj.（形容词）
Alone in kind or class; sole.
唯一的：在种类或级别中与众不同的；独特的
Standing alone by reason of superiority or excellence.
出众的：因杰出和优秀而突出的
adv.（副词）
Without anyone or anything else; alone:
单独地：没有其它别的事物；独自地：
例句：
room for only one passenger.
单人客房

At the very least:
仅仅：
例句：
If you would only come home. The story was only too true.
只要你肯回家来。这故事是千真万确的

And nothing else or more:
只有，仅仅：
例句：
I only work here.
我只在这里工作

Exclusively; solely:
专门地，唯一地：
例句：
facts known only to us.
这些事只有我们才知道

In the last analysis or final outcome:
最后的分析，最终结果：
例句：
actions that will only make things worse.
最后使事情更糟糕的行为

With the final result; nevertheless:
最终结局，仍然：
例句：
received a raise only to be laid off.
加薪的结果只是被派遣而已

As recently as:
最近地：
例句：
called me only last month.
上个月刚通知我

In the immediate past:
刚才：
例句：
only just saw her.
刚才还看见她了

conj.（连接词）
Were it not that; except.
假如；除非

With the restriction that; but:
条件是，但是：
例句：
You may go, only be careful.
你可以去，但要小心

However; and yet:
然而，毕竟：
例句：
The merchandise is well made, only we can`t use it.
这种商品做工精致，然而我们不能用

来源：
Middle English
中古英语
from Old English 3nloc
源自 古英语 3nloc
3n [one] * see one
3n [一个] *参见 one
-loc [having the form of] * see -ly
-loc [具有这种形式的] *参见 -ly

When used as an adverb,only should be placed with care to avoid ambiguity. Generally this means havingonly adjoin the word or words that it limits. Variation in the placement ofonly can change the meaning of the sentence, as the following examples show:
当only 用作副词时应注意避免意义模糊。 一般来说，这意味着把only 放在被限定词的旁边。 Only 的位置的改变， 会改变整个句子的内容，例如：
例句：
Dictators respect only force;
独裁者只认同暴力；

例句：
they are not moved by words.
他们不会被言辞所打动。

例句：
Dictators only respect force;
独裁者只重视权力；

例句：
they do not worship it.
他们不崇拜它。

例句：
She picked up the receiver only when he entered, not before.
他刚一进来她就接到了电话。

例句：
She only picked up the receiver when he entered;
她只在他进来的时候接电话；

例句：
she didn`t dial the number.
她没有拨电话。

Though strict grammarians insist that the rule for placement ofonly should always be followed, there are occasions when placement ofonly earlier in the sentence seems much more natural. In the following exampleonly is placed according to the rule:
虽然严格的语法学家主张应该遵循only 位置的用法规则， 但有时only 放在的句子开头，看起来十分自然。 下面例子中only 的位置是按规则安排的：
例句：
The committee can make its decision by Friday of next week only if it receives a copy of the latest report.
委员会只有在收到最后的报告后，才可以在下周五作出决定。

Placement ofonly earlier in the sentence, immediately after can, would serve the rhetorical function of warning the reader that a condition on the statement follows.See Usage Note at not
Only 的位置紧跟在 can 的后边且在句子开头， 可以利用倒装句型提醒读者后边是一个条件参见 not