none

Từ điển American Heritage Dictionary 4th

none (nŭn)pron.
1. No one; not one; nobody:
None dared to do it.
2. Not any:
None of my classmates survived the war.
3. No part; not any:
none of your business.adv.
1. Not at all:
He is none too ill.
2. In no way:
The jeans looked none the better for having been washed. [Middle English, from Old English nān: ne, no, not; See ne in Indo-European Roots + ān, one; See oi-no- in Indo-European Roots.] 
Usage Note: It is widely asserted that none is equivalent to no one, and hence requires a singular verb and singular pronoun: None of the prisoners was given his soup. It is true that none is etymologically derived from the Old English word ān, “one,” but the word has been used as both a singular and a plural noun from Old English onward. The plural usage appears in the King James Bible as well as the works of John Dryden and Edmund Burke and is widespread in the works of respectable writers today. Of course, the singular usage is perfectly acceptable. The choice between a singular or plural verb depends on the desired effect. Both options are acceptable in this sentence: None of the conspirators has (or have) been brought to trial. When none is modified by almost, however, it is difficult to avoid treating the word as a plural: Almost none of the officials were (not was) interviewed by the committee. None can only be plural in its use in sentences such as None but his most loyal supporters believe (not believes) his story. See Usage Note at every. See Usage Note at neither. See Usage Note at nothing.