[c.] Singular subjects joined by or or nor take a singular verb.

[d.] A subject consisting of two or more nouns joined by and takes a plural verb.

[e.] A verb should agree in number with the subject, not with a predicate noun.

[f.] In There is and There are sentences the verb should agree in number with the noun that follows it.

Exercise:

  1. The sound of falling acorns (is, are) one of the delights of an autumn evening. Eye strain through ill-fit glasses (is, are) injurious to the general health, but reading without glasses (is, are) often more harmful still.
  2. Neither the baritone nor the tenor (has, have) as good a voice as the soprano. The guitar or the mandolin (is, are) always out of tune.
  3. The Amazon with its tributaries (affords, afford) access to sea. The conductor of the freight train, along with the engineer and fireman of the passenger, (was, were) injured.
  4. Ghost stories late at night (is, are) a crime against children. My reason for knowing that it is six o'clock (is, are) the factory whistles.
  5. There (was, were) in the same coach a dozen singing freshmen. Years of experience in buying clothes (gives, give) me confidence in my judgment.