新概念英语第二册：第48课课文详解及语法解析
课文详注 Further notes on the text
1.Dentists always ask questions when it is impossible for you to answer. 牙科医生们总是在你无法作出回答的时候向你提出问题。
在when引导的时间状语从句中，it为先行主语，代指后面的不定式，for+人称代词/名词说明不定式表示的动作是谁做的：
It is not hard for you to help them.
你帮助他们并不难。
It was a mistake for me to come to the party.
我来参加晚会是错误的。
impossible通常不以人作主语，而以不定式或从句作主语：
It is impossible for him to help you.
他不可能帮你。
It is impossible that he will help you.
(译文同上)
2.In answer to these questions I either nodded or made strange noises.
作为对这些问题的回答，我不是点头，就是发出奇怪的声音。
(1)in answer to为固定短语，在这里表示“作为对……的回答”：
In answer to my question, Dan shook his head.
作为对我的问题的回答，丹摇了摇头。
这个短语的另一个含义是“响应……的请求”：
In answer to my request, he wrote a letter to George.
应我的请求，他给乔治写了封信。
(2)made strange noises, 发出奇怪的声音。“我”并不是有意发出这些声音，而是因为嘴里有药棉，又想回答医生的话造成的。
3.Meanwhile, my tongue was busy searching out the hole where the tooth had been. 与此同时，我的舌头正在忙着寻找刚拔掉的那颗牙的伤口。
(1)副词meanwhile表示“在此期间”、“与此同时”：
He won't come until ten o'clock. Meanwhile you can have a rest.
他10点以前不会来。在此期间你可以休息一下。
Mary was talking to me about her new dress. Meanwhile I was thinking about something else.
玛丽在和我讲她的新衣服。与此同时我却在想着其他事情。
(2)search out表示“找出”、“查出”、“搜出”等：
Have you searched out the books I needed?
你找出我需要的书了吗?
(3)where the tooth had been用的是过去完成时，因为在描述这件事的时候那颗牙已经不在了。牙齿尚在的时间是“过去的过去”。
4.When the dentist at last removed the cotton wool from my mouth…
当那位牙医最后将药棉从我嘴中取出时……
remove可以表示“拿去”、“除去”、“去掉”，通常结构为“remove +名词+from”;它也可以单独使用：
I've removed that picture from the wall.
我已经把那幅画从墙上拿走了。
Please remove your hat.
请摘下你的帽子。
语法 Grammar in use
复习第26～45课的部分语法
It is one of the ugliest faces(that) I have ever seen.
这是我见过的最丑陋的头像之一。(that在关系从句中作宾语，可省略)
There aren't many students who sing as well as she does.
在学生当中没几个人唱歌像她那么好。(who在关系从句中作主语，不可省略)
People are not so honest as they once were.
人们不再像以前那样诚实了。(not so/ as…as用于比较状语从句)
He had hardly had time to settle down when he sold the house.
他还没等安顿下来就卖掉了房子。(hardly…when用于过去完成时)
No sooner had I sat down than he came in.
我刚坐下他就进来了。(no sooner…than用于过去完成时;否定词位于句首时句子要倒装)
The box was so heavy that she couldn't lift it.
箱子太重了，她搬不起来。(so+形容词+that表示“如此……以至于”)
The thief got such a fright that he dropped the bag.
那个小偷吓得把提包都扔了。(such〈a〉+名词+that表示“如此……以至于”)
Billy is not at home at present. He's at school.
比利现在不在家，他在学校。(at+名词的用法)
