My ear tells me this is correct:

"The best I can do is give you a refund."

But what is the verb in the above sentence: "is", or "give"? I think "The best thing we can do" is a subject phrase, and I think "is" is the verb, but I'm not sure what's going on with the infinitive "laugh". I'm pretty sure "is give" isn't a valid tense.

Would it perhaps be safer to say, "The best thing I could do would be to give you a refund?"

Thanks for any insight -

I garbled some of the question. It should read:

My ear tells me this is correct:

"The best I can do is give you a refund."

But what is the verb in the above sentence: "is", or "give"? I think "The best I can do" is a subject phrase, and I think "is" is the verb, but I'm not sure what's going on with the infinitive "give". I'm pretty sure "is give" isn't a valid tense.

Would it perhaps be safer to say, "The best thing I could do would be to give you a refund?"

Thanks for any insight -

Ok, I realized this question should be in the general verbal section, so if someone wants to move it I won't complain :oops:

Doing a little research: it looks like "parallel structures" rule is important regarding the word "is", and verbs on either side of it should agree, so:

"The best I can do is give you a refund." [correct]
"The thing to do is to give you a refund." [correct]
"The thing to do is give you a refund." [incorrect]

I found that "an exception would be the infinitive of purpose: using a to-inf to say why we do something". So:

"Our shouting is to see who has the loudest voice" [correct]

I think I answered my own question.

Doing a little research: it looks like "parallel structures" rule is important regarding the word "is", and verbs on either side of it should agree, so:

"The best I can do is give you a refund." [correct]
"The thing to do is to give you a refund." [correct]
"The thing to do is give you a refund." [incorrect]

I found that "an exception would be the infinitive of purpose: using a to-inf to say why we do something". So:

"Our shouting is to see who has the loudest voice" [correct]

I think I answered my own question.

i find it highly unlikely that you would see a structure like this one on the test, but, for what it's worth, i would use the infinitive if the issue comes up:
the management can do no better than to give you a refund
this is definitely acceptable in formal written english, because infinitives can act as nouns.

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in any case, you should not, for gmat purposes, be considering first- and second-person sentences, because the gmat never uses anything but the third person.