keep as,keep for;desides,except;to of的区别

keep as,keep for;desides,except;to of的区别
keep as,keep for;desides,except;to of（意思指.的）的区别
（答好多分)
还有while和when的区别
会几个答几个

一、 except用于表示同类事物之间的关系,其意为"除……以外"、"除去".
1. except后面可接名词、代词、动词、副词、介词短语和从句等.如：
We have an English lesson every day except Sunday. 除星期天外,我们每天有一堂英语课.(接名词)
They all went to the park last Sunday except him. 除了他以外,上星期天他们都去公园了.(接代词)
Every day Mary does nothing except watch TV. 每天玛丽除了看电视以外什么都不干.(except后接动词时,一般为带to的动词不定式.但如果except前面有谓语动词do或其相应形式时,后面通常接省略to的动词不定式.如此句.)
He always goes to work by bike except recently. 除最近外,他一般都骑自行车上班.(接副词)
After breakfast the students went nowhere except to school. 吃完早餐,学生们除了上学就不到别处去了.(接介词短语)
My father usually goes to work by bike except when it rains. 除下雨天外,我爸爸通常骑自行车上班.(接从句)
2. except常用在all, whole, any, every, no等词,及anything, anybody, anyone, everything, everybody, everyone等不定代词之后.如：
She ate everything on the plate except the carrots.除胡萝卜外她把盘子里的东西都吃了.
I've cleaned all the rooms except the toilet. 除了厕所,我清扫了所有房间.
二、 except for用于表示对主要部分的肯定和对局部的否定.它不表示同类事物之间的关系,其意思为：
1. "除了……以外".如：
Smith is a good man, except for his bad temper. 史密斯除了脾气不好外,是个好人.
The movie was good except for the ending. 这部电影除了结尾之外都很好.
2. "除去为了……".如：
Mother wouldn't give him any money except for books and stationery. 除了买书和文具外,妈妈不给他任何钱.
3. "如果不是","若非".如：
Except for you, I would pass the exam. 如果不是你,我就会通过考试.
4. "except for+名词"结构一般可以改写成"except+that从句".如：
This will do except for the length.= This will do except that it is too long. 如果不是它太长的话,这会很好.
All are here except for the absence of Tina. = All are here except that Tina is absent. 除了蒂娜以外,大家都在这里.
三、 except与except for的互换
1. except与except for有时可以通用,不过,一般情况下,except for可置于句首,而except则不能.如：
Everyone is here except Tom. (或：Except for Tom everyone is here.)除汤姆外,大家都到了.
2. except与except for在句中也可互换.
一般来说,否定句中用except,肯定句式可以用except for来替换.如：
This article has no blunders except a few mistakes.这篇文章除了一点小错外没有大错.
此句可改为：This article is instructive except for a few blunders. 这篇文章除了有些错误外,是有教育意义的.
不过,在前后有相称的同类词语时,应用except,否则用except for.如：
We come to school every day except Sunday. 除星期天外,我们天天上学.(句中every day与Sunday同类)
This dress is ready except for the buttons. 衣服做好了,只是钮扣未缝上.(句中ready与buttons不同类)
四、 excepting是由动词转化而来的分词介词,用法较正式,含有较强的动态意味,意为"把……除外",与except在用法上有不同之处：
1. 可用于句首,或用于not, without, always等词后；
2. 其后常常用名词或代词.如：
Bruce answered all the questions excepting the last one. 除了最后一个问题外,布鲁斯都答出来了.
Excepting Sundays, the library is open daily. 除了星期天外,图书馆天天开放.
I think we must keep improving our English not excepting those who have mastered it. 我认为我们必须不断提高我们的英语水平,对那些已掌握了英语的人也不例外.
All the people in my family go to work every day, always excepting my youngest sister. 我家所有的人每天都上班,除了我那个最小的妹妹以外.
巩固练习：
用except, except for或excepting填空.
1. She usually goes to work on her bike ________ when it rains.
2. The whole staff, not ________ the heads of departments, went to the playground.
3. His account is correct ________ that some details are omitted (省略,遗漏).
4. The office is empty ________ Alice.
5. I would go ________ it's too late.
6. All the essays are good ________ John's.
7. Everybody must study, ________ those who have a better grasp of Marxism.
8. The wall was bare ________ a map of the world.
9. I have looked for my wallet everywhere ________ there.
10. I would join you ________ my headache.
11. We can ask him for some advice at any time ________ during his holidays.
12. His composition is good, ________ some spelling mistakes.
13. John wasn't remembered, ________ by some of us who had known him.
14. There was silence in the room, ________ the tick of the clock on the wall.
15. The pair of trousers fits me well ________ the waist of it is a little too small.
Key:
1. except 2. excepting 3. except 4. except for 5. except 6. except 7. excepting 8. except for 9. except 10. except for 11. except 12. except for 13. except 14. except for 15. except