Pro-verbs: do/do, do/could, could/do, etc.

[Erin]

Question

Can "do" replace only regular verbs? Or can it replace modals as well? And, conversely, can modals replace "do"?



Answer

The tense and other information of the "do" part depends on the "do" verb, not on the previous verb.

Examples:

Joe could speak Spanish better than I do.

In this sentence, I speak Spanish, but Joe is now living in Peru and has only Peruvian friends. Therefore, he could (end up) speaking better than I do (than I already speak).

Joe speaks Spanish better than I could.

In this sentence, Joe already speaks Spanish better than I will ever be able to.