Proper tense for this sentence? "The rapid spread of water-borne diseases in the town derive(d/s) from bacteria in the polluted rivers."

Question

I came across a question from an English practice book and I'm wondering whether the verb should be in simple past or simple present tense.

Unfortunately, the test instruction gave no additional context as the instruction was:

1.3 Complete the pairs of sentences below with the words from Ex 1.2. In each pair, you need the same word for both sentences. In the case of verbs, pay attention to the ending required, e.g., -s, -ed, -ing. In the case of nouns, you have to decide whether the singular or plural form is appropriate.

with the original question being,

Some of the most important vitamins required to stay healthy can be . . . from oily fish. The rapid spread of water-borne diseases in the town . . . from bacteria in the polluted rivers.

Given the information above, which sentence has the proper tense?

"The rapid spread of water-borne diseases in the town derived from bacteria in the polluted rivers."

or

"The rapid spread of water-borne diseases in the town derives from bacteria in the polluted rivers."

Thank you.

Answer 1

It is a poorly designed question.

In the first sentence, about oily fish, “derived” is correct. It is being used as a passive participle and does not indicate a tense.

In the second sentence, about pollution, either “derives” or “derived” is grammatically acceptable. Which tense is appropriate depends on whether what is being discussed is currently happening or happened in the past.

The instructions say to use the SAME word in both sentences. Thus, what is intended is “derived” for both sentences. But there is no grammatical lesson to be extracted from the second sentence.

MAJOR EDIT: Based on the comments below, I admit my error in asserting the exercise to be poorly designed. Instead, it is designed atrociously.

The exercise says “same word.” It is obvious that the word to be chosen in the “oily fish” example must be a passive participle. Not one of the twelve choices given is a participle. It is also impossible to fit any choice provided into the “rapid spread” sentence because no choices are given that are verbs in the past tense or third, singular, present tense.

What seems to be intended is that the same root meaning is to be used in each sentence without regard to inflectional variation.

That means either “derives” or “derived” is a grammatically acceptable choice. This is not a test of tenses and inflection but of lexical meaning.

So in the question shown in the comment below, the choices intended are likely “respond to” and “responding.”

Terrible design. The student thinks it is about tense, which is not possible because some of the word choices are adjectives.

And we are left with Ellie’s comment that “derive” is not the most apt way to say “is (or was) caused by.”