Neither is a word about which many theoret­ical rules have been excogitated, beginning back in the 18th century, without regard to actual practice. Practice that deviates from the rules is regularly censured as error, regardless of the stature of the offending writer. But irregular (not to say, unruly) practice has continued in blithe disregard of the censorious grammarians, as materials collected in the OED, volume 2 of Jespersen 1909-49, and an article by William M. Ryan (American Speech, Fall-Winter 1976) abundantly attest. The worm in the apple of theory here is usually notional agree­ment, which was unknown to the grammarians who devised the rules and is unknown to or ignored by the handbook compilers who repeat them. We will take a look at four instances where precept and practice diverge.

1. Pronoun. Neither, the rules assure us, is singular. However, actual practice requires us to temper the abso­lute form of the rule and say that neither is usually sin­gular. The reason it is sometimes plural is easy to see when you think about it. Neither serves as the negative counterpart of either, which is usually singular. But it also serves in the same way for both, which is usually plural. Suppose, for instance, you have written "when both are dead." If you wanted to use alive instead of dead, you might come up with Shakespeare's solu­tion:

Thersites' body is as good as Ajax'
When neither are alive
                    —Cymbeline, 1610

Other writers have done the same:

Both writ with wonderful facility and clearness; nei­ther were great inventors —John Dryden, Preface to Fables, Ancient and Modern, 1700 (in OED)

Neither belong to this Saxon's company —Sir Wal­ter Scott, Ivanhoe, 1819 (in Jespersen)

Neither were as good or as popular as his First — Time, 20 July 1942

The major characters dissolve into a stream of anx­ieties and musings, the minor ones are ferociously eccentric; and neither matter —Irving Howe, New Republic, 16 Nov. 1953

He had two job offers, but neither were ones he felt he could accept —Diana Diamond, N. Y. Times, 20 Oct. 1974 (in Ryan)

Though we will not illustrate the fact extensively, it is worth noting that neither by itself is more frequently singular:

Neither has a theatre of its own —Ronald Hayman, The Set-Up, 1973

... neither was able to go —K. M. Elisabeth Murray, Caught in the Web of Words, 1977

The singular number of neither is most likely to be ignored when it is followed by of and a plural noun or pronoun, for then both notional agreement and the prin­ciple of proximity (or "attraction" as Jespersen calls it) pull in the direction of a plural verb. A few commenta­tors, such as Evans 1957, Copperud 1964, 1970, 1980, and Perrin & Ebbitt 1972, recognize this construction. The pull of these two forces is obvious in the first exam­ple below, where neither without the of phrase is singular:

Neither cares about decent homes for the citizens. Neither of these dragons care about skyrocketing prices—Congressional Record, 18 July 1951

... neither of 'em understand Mathematicks — Thomas Shadwell, The Sullen Lovers, 1668

... neither of them are a bit better than they should be —Henry Fielding, Tom Jones, 1749 (in Jespersen)

... but neither of these are the causes of it —John Ruskin, The Crown of Wild Olive, 1866 (in Jespersen)

Do you mean to say neither of you know your own numbers? —H. G. Wells, A Modern Utopia, 1905 (in Jespersen)

Neither of these two last examples were so intended —William Empson, The Structure of Complex Words, 1951

... neither of which are available in this country — Peter Stockham, in Times Literary Supp., 15 June 1967

... Marx and Trotsky, neither of whom were notably gentle or vegetarian —Dwight Macdonald, Esquire, October 1966 (in Perrin & Ebbitt)

... the two hot spots, neither of which have ever been especially praised for their food —Judy KJemesrud, quoted in Simon 1980

Neither of these indicators are particularly accurate —Pat Ingram, Chronicle of the Horse, 13 Jan. 1984

Even in this construction a singular verb is very common:

... with whiskey and a deck of cards, but most of the time neither of these was available —J. L. Dillard, American Talk, 1976

Neither of you speaks a word until you're in the cab —Jay McInerney, Bright Lights, Big City, 1984

... neither of us was rational enough to be con­vinced of the other's position —John Barth, The Floating Opera, 1956

The pronoun neither, then, is not invariably singular, though it is more often so. When formal agreement obtains, it takes a singular verb. When notional agree­ment obtains, it takes either a singular or plural verb. These constructions are neither nonstandard or erro­neous. If you are writing something in a highly formal style, you will probably want to use formal agree­ment throughout. Otherwise, follow your own inclina­tion in choosing singular or plural constructions after neither.

2. Neither ... nor, neither... or. Opinion on this topic seems nearly unanimous:

Neither cannot grammatically be followed by or — Campbell 1776

Always after neither use nor —Bierce 1909 neither   It's followed by nor, not or —Trimble 1975

... neither... is followed by nor, not or —Reader's Digest 1983

But although nor is usual after neither, or has also been used quite often from the 16th century to the present. It was Jonathan Swift who got Campbell exercised:

A petty constable will neither act cheerfully or wisely —Some Free Thoughts &c, 1714

The neither... or construction is not at all rare:

... he would neither go with me, or let me go with­out him —Daniel Defoe, Moll Flanders, 1722

... for I neither ride or shoot or move over my Gar­den walls —Lord Byron, letter, 9 Sept. 1811

"... if a man is neither to take orders with a living or without...." —Jane Austen, Mansfield Park, 1814

An ordinary country girl, neither pretty or plain — Joyce Cary, quoted in Time, 20 Sept. 1948

Neither McCarthy's bigoted intolerance or Truman's excessive toleration can be allowed to weaken the government —Michael Straight, New Republic, 26 Mar. 1951

But justice is neither old or new —Mark Van Doren, American Scholar, Autumn 1951

... an author who is neither an infant, a fool, or a swindler—Eric Bentley, New Republic, 16 Feb. 1953

Neither Cadwallader, Oliffe or Mitcham would claim ... —Tom Mangold, The Listener, 1 Nov. 1974

... the satellites are in thermal balance, neither heat­ing up or cooling off —Robert C. Cowen, Christian Science Monitor, 23 Dec. 1982

Now, we can see no particular reason why anyone would prefer or to nor in these examples (except perhaps in the one from Jane Austen, where parallelism becomes a consideration). But obviously or seemed idiomatic to these writers, and their sentences are perfectly compre­hensible. We suspect that you, like most people, will pick nor after neither. But if you do happen to use or instead, you will have committed no dreadful solecism.

3.  Must neither refer to two only? The answer, as you might suspect from having read a few of the examples in the preceding section, is no. A few commentators (Follett 1966 and Fowler 1926, 1965, for instance) hold out for two, but more consider what Fowler called the loose use to be neither solecistic nor nonstandard. It dates back to the 17th century, according to the OED. The adjective, the pronoun, and the conjunction are all sometimes used of more than two; such use is quite common with the conjunction.

I could do neither one of those three things —Henry Adams, letter, March or April, 1894

The French are descended from Gauls, Romans, and Germans, and neither of these elements was a dis­tinct race —Carl D. Buck, Comparative Grammar of Greek and Latin, 1933

... neither of these last three materials is found in Japan —G. B. Sansom, Japan: A Short Cultural His­tory, rev. ed., 1943

... neither tea, nor coffee, nor lemonade, nor any­thing whatever —Samuel Johnson, in James Boswell, Life of Samuel Johnson, 1791

Neither Hamlet, nor Macbeth, nor Othello, nor Douglas, nor The Gamester presented anything that could satisfy even the tragedians —Jane Austen, Mansfield Park, 1814

Neither you nor I nor anyone we know —Archibald MacLeish, letter, 27 Mar. 1920

... people who were neither beautiful, exciting, nor amusing —William Butler Yeats, Dramatis Per-sonae, 1936

... this optimism, shared by neither labor, agricul­ture, nor industry —Paul A. Samuelson, New Repub­lic, 18 Sept. 1944

... the rigid enforcement of antique decorum will help neither language, literature, nor literati —James Sledd, English Jour., May 1973

We could cite dozens more. You may have noticed that the adjectival and pronominal uses are a bit jar­ring—they catch the attention more than they should— but the conjunctional uses seem humdrum. This sug­gests that you will probably want to avoid the first two—none is a perfectly good substitute—but you can use the conjunction freely. Note that nor is sometimes repeated and sometimes omitted for the intermediate words.

4. "Neither... nor" and verb agreement. Fowler 1926 is a bit irritated that Samuel Johnson and John Ruskin, as cited in the OED, transgressed his rule, which requires that if both subjects are singular the verb be singular. Fowler, of course, did not or would not understand notional agreement, which is what Johnson and Ruskin were following. Here is Johnson:

Neither search nor labour are necessary —The Idler, No. 44, 1759 (OED)

Dr. Johnson used singular agreement too:

... neither reason nor revelation denies —letter, 25 Sept. 1750 (in Fitzedward Hall 1873)

Conjunctional neither ... nor, like the pronoun nei­ther, acts as a negative for either... or (construed as sin­gular) and for both ... and (construed as plural); agree­ment therefore may be either singular or plural— notional agreement, pure and simple. Here are several examples with two singular subjects and with either a singular or a plural verb:

Neither wood nor plastic conducts heat the way metal does —And More by Andy Rooney, 1982

... neither force nor acceleration is directly denned —David Berlinski, Black Mischief, 1986

Neither moon nor Mars are habitable —Ashley Montagu, Vista, January-February 1970

Neither Cox nor Kepshire has shown any ill effects —Craig Neff, Sports Illustrated, 22 July 1985

... neither my father nor I were by nature inclined to faith in the unintelligible —George Santayana, Persons and Places, 1944

... neither George—nor the audience—knows what dragons await him —David Ansen, Newsweek, 16 June 1986

... has lasted almost a century because neither light, heat, nor humidity affect it —Ellen Ruppel Shell, Science 84, September 1984

Neither the Los Angeles Times Book Review nor the Washington Post Book World, for instance, name reviewers for their notices of new paperbacks —Pub­lishers Weekly, 2 Aug. 1985

Neither ... nor with two (or more) singular subjects, then, is governed by notional agreement and may take either a singular or a plural verb, as if the writer were imagining it as the negative of "either this or that" or the negative of "both this and that." When the subjects are plural, or the last subject is plural, a plural verb is expected:

Neither montana nor Mexican origins are at all likely —Edward P. Lanning, Peru Before the Incas, 1967

A few books—Fowler 1926, Evans 1957, Chambers 1985—give conflicting advice on sentences containing constructions like "neither she nor I." Our evidence for such constructions is slim, but it shows that in actual practice (see the Santayana example above) the plural verb is usual.

If you are a native speaker of English, you will prob­ably follow notional agreement without thinking, just as Samuel Johnson did. If you need a rule to follow con­sistently, use formal agreement—singular verb with sin­gular subject and the verb to agree with the nearest sub­ject otherwise. Formal agreement is always the safe choice in cases where you are uncertain.(资料出处：韦伯斯特英语用法词典)