B: The emergency lights atop the fire trucks were flashing. Lights is your noun and were acts like your verb.
for A it should be: The exhibits on the lower level are not currently open to the public.
for C it should be: That man, wearing sunglasses, seems to be an undercover police officer.
for D it should be: Perry, like his younger sister Pauline, writes very neatly.
Hopefully this helped and good luck.
(A)
(B)
(C)
(D)
(E)
I also concur that answer B has an error.
B: he was going to give...
So lets rewrite the whole thing. In order to prepare for the speech he was going to give to all of the parents and teachers at the school, George practiced speaking in front of a group of his friends.
After correcting B, the entire sentence flows more nicely. Hopefully this helped and good luck
a. has warned sailors
b. That old lighthouse
c. for many decades
d. has warned
I believe the adverbial phrase in this sentence is (C) for many decades.
It modifies the verb, warned.
The answer to your question would be that the verb that should be used with the helping verb "had" in the sentence is the following one: frozen. That is, the sentence would be as follows "despite the grove owners' hard work, the orange crop had frozen overnight.
The auxiliary verb "have" in the past indicates that the following verb should be in the past participle form for the sentence to be in the past perfect tense. The past participle of the verb "to freeze" is "frozen".