In Predicates^x, Numbers^x, Plurals^x

http://pinker.wjh.harvard.edu/articles/media/1994_01_24_thenewrepublic.html Probably no "grammatical error" has received as much scorn as "misuse" of pronoun case inside conjunctions (phrases with two parts joined by is an object that requires object case, it does not mean that is an object...

I often see sentences where the object noun or the predicate noun is in disagreement with the subject in number. In most case this kind of imbalanced singular noun is followed by a sentence or clause that explains it. I feel this disagreement would be intentionally used by writers to attract...

How is it correct: "a number of people have done this" or "a number of people has done this"? I would think that as long as the subject of the sentence is singular ("a number") then the predicate (has/have), should be singular, rather than plural. However, English is not my first language, and...