Oﬃcial measurements of the Mississippi River’s length vary: according to the US Geologic Survey, the river is 2,300 miles
long, whereas the Environmental Protection Agency records its length as 2,320 miles. This disparity can be explained in part
by the fact that rivers such as the Mississippi expand and contract as ______ sediment.
they accumulate
one accumulates
it accumulates
we accumulate
Choice A is the best answer. The noun that goes with "expand and contract" is "rivers," a plural noun. "They" is a third-person
plural pronoun, so it can correctly stand in for "rivers."
Choice B is incorrect. This choice creates a pronoun-antecedent agreement error. "One" is a singular pronoun, but the noun
that goes with "expand and contract" is "rivers," a plural noun. Choice C is incorrect. This choice creates a pronoun-
antecedent agreement error. "It" is a singular pronoun, but the noun that goes with "expand and contract" is "rivers," a plural
noun. Choice D is incorrect. This choice creates a pronoun-antecedent agreement error. The noun that goes with "expand
and contract" is the plural noun "rivers." Rivers are not people, so "we" can’t be used to stand in for it.