## Is it necessary to add "do it" in the following case?

8

My headache was so bad by then I could barely go to class. And when I managed to do it, I couldn't listen to the professor at all.

Can I just write, "And when I managed to, I couldn't..."?

2I'd use "do so", but I don't think omitting is problematic. Still, that's a thought. I'm waiting for answers, just like you. – M.A.R. – 2015-02-25T13:52:39.550

Interestingly, you can even leave out the "to", in a phrase like "and when I finally managed" or "and when I did manage", but not "and when I managed". – Dewi Morgan – 2015-02-25T23:49:11.430

I think it's alright to drop "do it" in that sentence. – andreazx – 2015-02-25T13:52:42.627

10

Yes, you can. The to in "And when I managed to, I couldn't..." links to verb in the preceding sentence, which is go. So, when you say "And when I managed to, I couldn't..." the to acts as a to-infinitive for to go and thus it actually means "And when I managed to go, I couldn't...". Hope that helps.

3

I would say that it sounds wrong. It should be either "to," or "to do so,".

So, not only can you do so, I would say you should do so.

3

No. It is not necessary, you can leave out "do it".

My headache was so bad by then I could barely go to class. And when I managed to, I couldn't listen to the professor at all.

In the second sentence above, 'to' acts as a pro-verb, which is like a pronoun, but for verb phrases.

That Wikipedia article includes this explanation and example:

Since a to-infinitive is just the particle 'to' plus a bare infinitive, and a bare infinitive can be elided, the particle 'to' doubles as a pro-verb for a to-infinitive:

Clean your room! —I don't want to [clean my room]. He refused to clean his room when I told him to [clean his room].