Dave's ESL Cafe's Student Discussion Forums

[walkabout]

I gave the proverbial �Lies are a necessary evil� as a debate topic and one of my ESL students (A student teacher) told me �are a� is grammatically wrong. ie It should be lies are necessary evil(s) I know the form is correct in so far as it can be found in popular use and publication but I am at a loss to explain it in grammatical terms.

I believe the following are also all true:
Potatoes are a vegetable
Potatoes are vegetables
Potatoes are vegetable

Could someone please help me out with a grammatical explanation of why each are right or wrong?

[lotus]

Hi walkabout:

What we're trying to say is that "Lying is a necessary evil." We often say it as "Lies are a necessary evil."

Let's look at the first sentence. What we're saying is that the the "act of lying" is a necessary evil, not the lie itself. We can rephrase it by saying "evil lying."

When we look at the second sentence, it says that "lies" (a noun) is a necessary evil. We can a shorten it by saying "evil lies."

Let's replace "lies" with "they." The sentence becomes "They are a necessary evil." So now, the argument becomes which is more correct?

1) They are a necessary evil.
2) They are necessary evils.

The second sentence is grammatically correct. But, so is the first sentence. This is because "they" can sometimes be treated as singular.

Green vegetables (plural) are a good source (singular) of vitamins.
Her brothers (plural) were a pain (singular) in the butt.

Lies (plural) are a necessary evil (singular).

So, why is number 1 more correct? It is because we think of lying (or lies) as a singular vice (bad habit). So, we generally say "Lies are a necessary evil."

This example shows that technical English is not always common English. It also shows that your student is very astute (intelligently alert).

From the discussion above, all the phrases below are correct. That's because both potatoes and vegetables can be treated as singular.

Potatoes are a vegetable
Potatoes are vegetables
Potatoes are vegetable


--lotus

[walkabout]

Thank you very much for your help Lotus. I think I can learn something from the way you broke the problem down too.

Regards
John