All ...are not ...

I don't think people tend to say 'all the children are not at school'. I mean, it just doesn't sound right. We tend to say 'There is no one at school.' This means 沒有人在學校裡.

I can only think of one case where people will use the first example given above by you, that 'all the children are not at school'. This should mean, they all have left school, perhaps have gone on a field trip or gone back home after school.

One essential thing I have to point out is your use of prepositions in here. When you say, all the children are not at school', this definitely does not mean that they do not attend colleges or do not receive schooling, rather that they are not AT that place, but somewhere else. It should be 'none of the children are IN school', if you mean to talk about their absence.

To clarify things better, I should make a little conclusion:
At school is referring to their location, where they are at the moment. They are still in/attending school as their physical bodies are inside the school.
In school refers to their attendance, whether they are absent, late, or here.

Back to your question, before answering them, I would like to make you aware of your misunderstanding of the meanings of the sentences in the above. This is shown by the Chinese meanings written down by you, which do not share the same meanings with the original english sentences.

'Not all the children are at school.' does not have a meaning of 並非所有的孩子都上學. If you wish to say 並非所有的孩子都上學 in English, the correct way to say it is not every child has the right to go to/attend school or not every child goes to/attends school. 'Every' is to replace 'all' because 'all' in this case is simply not fluent.


2011-10-18 04:14:32 補充：
You have made the same mistake in the next example, b. Grammatically, 'none of the children are at school' is flawless, but meaning-wise, you have not grasped the true meaning of it. This means 沒有小朋友在學校裡. If you wish to say 所有孩子都不上學 in English, similarly you should put it as

2011-10-18 04:14:49 補充：
none of the children are in school if they all refuse to go to school which results in their absence. In a more likely event, where they do not get the equal chance to attend schooling, we tend to say none of the children goes to school/ attends schools. In addition,

2011-10-18 04:15:13 補充：
you may want to argue back by saying all of them deserve the right to be in school.

I suppose it's a bit Chinglish to use 'all' to replace all of such descriptive cases. Just remember there are two other words in English: every and none.

2011-10-18 04:15:19 補充：
'All' usually pairs up with some positives e.g. All ARE polite. If no one is polite oppositely, as I have already hinted, we say none is polite or all ARE rude, instead of all are not polite.

I hope everything's clear for you now. :)

2011-10-18 04:16:14 補充：
There isn't enough space here to complete my answer, so I have left some bits in the feedback section. Go and check it out.

其實有個比較簡單的看法的

all...not便是全部不是
not...all便是不全部

All children are not in school = 全部小孩都不在學校裏(不用上學)
Not all children are in school = 不是全部小孩都在學校裏(上學)

All of you are not bad = 你們全都不壞(差勁)
Not all of you are bad = 你們不是全都壞(差勁) = 你們當中有些壞(差勁)但有些還是好(令人滿意)的