All I can do is wait

All I can do is wait
 

which one is the correct and why?

All I can do is wait
all I can do is to wait

I believe that is the first one the right.

They are both correct, but the first sounds more natural to my ears.

You would say: "I believe the first one is right".

Why do we leave the to-infinitive out?

hi rdb - as tomisimo observed, both are technically correct, but the first
one is preferred; the reason is simply common usage according to the
ways in which languages gradually change.

hermit

Thank you for your advice.


I must avoid to use frequently the word THAT in all the text, only I should use it when it necessary.

Thank you.

Sí, y debiera recordar que siempre se debiera usar "que" en español:D

How would you say this phrase (idiomatically) in Spanish?

You're asking me.

Therefore, I feel the obligation to answer you.

Idiomatically, I would say it as far as you can understand the word translated.

Then it's sound in Spanish so Idiomaticamente.


I hope that can help you.

Todo lo que puedo hacer es esperar.
No puedo hacer otra cosa que esperar.

Adding to Robindesbois:

Sólo puedo esperar.
No puedo hacer más que esperar.