only的语法问题我在书上看到有时放在系动词前,又有的放在系动词后,那到底该怎么看它呢?

only的语法问题我在书上看到有时放在系动词前,又有的放在系动词后,那到底该怎么看它呢?
only的语法问题
我在书上看到有时放在系动词前,又有的放在系动词后,那到底该怎么看它呢?

only的语法问题我在书上看到有时放在系动词前,又有的放在系动词后,那到底该怎么看它呢?
1
only用法拾零
许文龙
only是一个在英语中出现频率很高的词,它的意思繁多,用法复杂,不少学生常误用.
一、only用作形容词
1. 与the连用,意为“惟一的”,作定语.如：
John is the only boy in his family.
约翰是家里惟一的男孩.
She is the only girl here who knows how to drive a car.
她是这儿惟一会开车的姑娘.
Jeremy is the only friend who lives near, all my other friends live far away.
杰里米是我惟一住得近的朋友,其余的朋友都住得很远.
2. only可修饰复数名词,意为“仅有的、惟一的一些”,作定语.如：
They were the only people present.
出席的只有他们这些人.
3. 与an连用,意为“单独的”,作定语.如：
Jim was an only son of his parents.
吉姆是他父母的独子.
4. 与the连用,意为“最好的、最适当的”,作定语.如：
She is the only person for the job.
她是做这项工作的最佳人选.
He is the only man for me.
对于我来说,他是最合适的人.
The only thing to do on a hot day is to go swimming.
在热天最理想的事就是去游泳.
二、only用作副词
1. 常位于所修饰的动词、短语或从句前,意为“只是、仅仅”.如：
At present we can only wait and see.
目前我们只好等一等看.
I only touched it.
我只不过摸了它一下.
I only regret that I have but one life to lose for my country.
我惟一遗憾的是：我仅有一次生命可以贡献给我的祖国.
He only walks to save money��he doesn”t really like walking.
他只是为了省钱而步行,并不是真正喜欢步行.
Father gave me this computer only for my birthday.
只是因为我过生日,父亲才送给我这台电脑.
My sister is in bed only because she is ill.
我姐姐在床上躺着,仅仅是因为她病了.
2. 意为“反而”.如：
Failure only strengthened our determination.
失败反而使我们的决心更坚定了.
3. only和不定式连用常构成结果状语,表示与预料相反的结果,意思是“竟然……、结果……”.如：
He studied hard only to fail in the exam.
他这么用功,竟然在考场上失利.
He rushed all the way to the station only to miss the train.
他一路冲往车站,结果还是错过了火车.
My wife went home in a hurry only to find the door locked.
我妻子急忙回到家,结果却发现门锁着.
He tried a second time only to fail again.
他再试一次,竟然还是失败了.
三、用作并列连词
用作并列连词时,意为“但是、可是、可惜、不过”.如：
This dictionary is just what I want, only it costs too much.
这本词典正是我想要的,但是太贵了.
He is always ready to promise help, only he never keeps his promise.
他总是轻易许诺提供帮助,但是他从不遵守诺言.
The flowers are lovely, only they have no scent.
这些花朵很好看,可异没有香气.
I would do it with pleasure, only I am too busy.
我倒是很高兴去做,可是我太忙了.
You may come at any time, only you had better let me know beforehand.
你什么时候来都行,不过最好先告诉我一声.
四、only在句中的位置
only在句中的位置不同,会使全句的意思或着重点有所不同,一般来讲,only应紧接在它所修饰的词之前.试比较：
Only Tom watches TV at home on Sunday.
只有汤姆星期天在家看电视.（修饰主语）
Tom only watches TV at home on Sunday.
汤姆星期天在家只是看电视.（修饰谓语）
Tom watches only TV at home on Sunday.
汤姆星期天在家看的只是电视.（修饰宾语）
Tom watches TV only at home on Sunday.
汤姆星期天只是在家看电视.（修饰地点状语）
Tom watches TV at home only on Sunday.
汤姆只是星期天在家看电视.（修饰时间状语）
五、only与倒装语序
only所修饰的副词、介词短语或状语从句位于句首时,要用倒装语序.如：
Only then did I realize the importance of health.
到那时我才认识到健康的重要性.
Only thus can we finish the task ahead of time.
只有这样我们才能提前完成任务.
Only in this way can you learn from your mistakes.
只有用这种方式你才能从你的错误中吸取教训.
注意：only修饰主语时,句子不需要倒装.
Only he knows the truth.
只有他知道真相.
Only socialism can save China.
只有社会主义才能救中国.
Only she understood him.
只有她才理解他.
Only very careful readers can find this mistake.
只有非常细心的读者才会发现这个错误.
六、only的习惯用法
1. only too意为“很、非常、实在”.如：
We are only too pleased to watch this TV play.
我们非常喜欢看这部电视剧.
The news was only too true.
这消息是极其真实的.
I am only too glad to help you.
我实在很高兴帮助你.
2. only just（加强just的语气）意为“好容易、刚才、刚刚”.如：
The plane has only just taken off.
飞机刚刚才起飞.
I was only just in time for supper.
我好容易赶上吃晚饭.
3. if only意为“但愿、要是……就好了”,常引导虚拟语气的条件句或感叹句.如：
If only we had arrived in time, we would not have missed the train.
要是我们按时到,就不会误车了.
If only I were younger!
要是我年轻些就好了.
If only it would stop raining!
但愿雨停下来.
注：if only有时也可以引导陈述语气的真实条件句,意为“只要……”.如：
If only it clears up, we”ll go.
只要天一放晴,我们就去.
4. only if引导陈述语气的真实条件句,意为“只要”.如：
Only if you study hard, you will pass the exam.
只要你努力学习,就会通过考试.
5. not only…but also…意为“不但……而且……”.如：
Lu Xun was not only a great writer, but also a great thinker.
鲁迅不但是个伟大的文学家,而且是个伟大的思想家.
注：使用not only…but also的几个要点：
（1）连接主语时,谓语动词要与邻近的主语保持一致.如：
Not only he but also I have been to the Great Wall.
不但是他而且我也到过长城.
（2）连接谓语时,not前不可有助动词.如：
I not only heard it, but also saw it.
我不但听见,而且亲眼看见了.
He not only said it, but also did it.
他不但说了,而且也做了.
（3）连接除主语外的其他成分时,如果位于句首,not only后的主谓需要倒装,但but also后的主谓不能倒装.如：
Not only has he been to Canada, but also he knows some Canadians.
他不但去过加拿大,而且认识一些加拿大人.
6. one and only意为“惟一的”.如：
It is my one and only hope.
这是我惟一的希望.
参考资料：http://www.chinaedu.com/101resource004/wenjianku/200403/101ktb/lanmu/F10E0345/F10E0345.htm