I am quoting this from OG12
A surge in new home sales and a drop in weekly
unemployment claims suggest that the economy might
not be as weak as some analysts previously thought.
(A) claims suggest that the economy might not be
as weak as some analysts previously thought
(B) claims suggests that the economy might not be
so weak as some analysts have previously
(C) claims suggest that the economy might not be
as weak as have been previously thought by
(D) claims, suggesting about the economy that it
might not be so weak as previously thought by
(E) claims, suggesting the economy might not be as
weak as previously thought to be by some
Agreement; Grammatical construction
The plural subject of this sentence (surge and drop)
requires a plural verb, suggest. Th e object of this
verb, the clause beginning with that, should be
presented in as clear and direct a manner as
A Correct. Th e plural subject is matched with
a plural verb.
B Th e singular verb suggests does not match
the plural subject of the sentence.
C Th e sentence off ers no plural subject to fi t
the passive verb have been thought.
D Th is construction is awkward, wordy, and
imprecise; it also lacks a main verb; there is
no reason to use passive voice, and suggesting
about the economy that it might … introduces
extra words that contribute nothing to the
meaning of this sentence fragment.
E Th e passive construction makes this
unnecessarily wordy; the lack of a main verb
makes this a sentence fragment.
What they are trying to say is that there is a plural subject in this sentence (two subjects). The "surge" itself is not plural, but the "surge and drop" together is a plural subject since they are two items.
Tom and Jerry suggest that we stay.
Tom is singular and Jerry is singular, but together they are plural therefore we use "suggest"
A surge and a drop suggest that . . .
Surge is singular and drop is singular, but together they are plural