Gerund, infinitive or root form

Question

“Once you crossed the whole camp on foot, asking for a glass of water is not a surprise”.

I used the gerund (asking) because it sounds to me like the correct form in this case, once I couldn’t find an explanation which helped.

Should I have used simply “ask” or “to ask” instead?

Moreover, when I add an adverb to the sentence, I feel like I should use the root form (bare infinitive, without “to”) of the verb:

“Once you crossed the whole camp on foot, politely ask for a glass of water is not a surprise”.

Is it right?

Answer 1

The second clause of your sentence contains the verb is, so it requires a noun clause as a subject. A simpler example would be

riding is fun

There are two choices of noun form for a verb- a gerund or a to-infinitive. In some special cases, you should use a bare infinitive, but this isn't one of them.

This article explains how you should choose between gerund or to-infinitive. In this case, it revolves around whether you are talking about a real or a hypothetical situation. Unfortunately, the tenses in your sentence are a bit mixed up, so it's difficult to tell whether it's real or hypothetical. Let's make two grammatically correct versions, one for gerund and another for to-infinitive:

After you crossed the whole camp on foot, asking for a glass of water was not a surprise. - real, past

If you were to cross the whole camp on foot, to ask for a glass of water would not be a surprise. - hypothetical

Adding an adverb does not change at all the type of verb to use:

After you crossed the whole camp on foot, hurriedly asking for a glass of water was not a surprise. - real, past