Helping Verb

[rte.sushil]

In the rare cases, in which tenses don't need to match, the exact verb form missing after the helping verb should be present elsewhere in the sentence:

Wrong: Our cars were designed to inspire envy, and they ARE
Correct: Our cars were designed to inspire envy, and they DO

I have few questions as below:

1.) Meaning of the sentence:
....tenses don't need to match, the exact verb form missing after the helping verb should be present elsewhere in the sentence:
It means that if we need to change tenses then repeat the whole verb in the new tense
So why can't we say:
Our cars were designed to inspire envy, and they ARE designed to inspire envy. ("were" and "are" are different tenses )

2.)
I think i am not 100% clear with statement: "the exact verb missing after the helping verb should be present elsewhere in the sentence". Please elaborate
According to me , exact verb form means "are verb+ing or does/do/did verb+(s/ /ed) or has/have verb+(ed)"?

3.)
Right: Our cars were designed to inspire envy, and they DO
It means : Our cars were designed to inspire envy, and they DO (inspire envy)
What if , the sentence is:
Our cars were designed to be the best, and they are, right?
Be -> represents quality so ARE.
inspire-> represents action so DO

4.) What if the sentence is not passive:
He wanted to design inspiring cars and he does/did
He wanted to design inspiring cars and he does/did (design inspiring cars)
//as per the same logic in (3)[-> they DO (inspire envy)]


Please throw light on above points.
Thanks!

[jlucero]

1) You could say that sentence, but as you mentioned, it's a very different (and kind of absurd) meaning. In the sentence, there's no question as to how the cars were designed, so we shouldn't clarify that they were designed a certain way and they are designed that way. You could make a different sentence that would be logically correct if you said: our cars were designed to inspire envy and they are still today. This would emphasize the difference between how cars were designed in the past and how they are still designed today. But the "still today" emphasizes that difference that's not implied in the examples you stated.

2) "the exact verb missing after the helping verb should be present elsewhere in the sentence" = inspire. When you give the second half of the sentence, "they do", it is a sentence, but is very ambiguous. What's missing is the exact verb that would logically attach at the end of that sentence: "they do inspire (envy)". The rule here is to find some other part of the sentence that could logically fit back into the shortened clause.

3) Your example would be highly unlikely on the actual GMAT, because there are two forms of "be" in that sentence, making your example ambiguous. "Our cars were designed to be the best, and they are". So "they are designed to be the best" or "they are the best". Ambiguity is what we're trying to avoid with these rules.

4) Completely acceptable.