"Que vs a" after verbs

[TomerAgmon]

I have to...
I need to...

To substitute "to", sometimes "que" is used and sometimes "a". Is there some sort of rule? Or is it determined by the verb?

[poli]

To have to is tener que. Tiene que recordarlo. It's easy use and very useful

To need to necesitar+ infinitive is a similar usage, but it doesn't use que.

[AngelicaDeAlquezar]

Poli is right. I will just add that the preposition needed is determined by the verb. The use of prepositions is one of the most difficult things when learning a foreign language, but with practice one ends up developing an intuition for the verb structures.

[TomerAgmon]

That helps a lot, thanks. I would mention though that after "necesitar", "que" is actually used... At least from my experience

[AngelicaDeAlquezar]

Oh, yes, but then it is translated as "to need that", rather than "to need to".

- Necesito comprar pan. (necesitar + infinitive)
I need to buy bread.
- Necesito que Juan compre pan. (necesitar + que + subjunctive)
I need that Juan buys bread.

- Necesitas comer más verduras. (necesitar + infinitive)
You need to eat more vegetables.
- Necesitas que tu comida tenga más verduras. (necesitar + que + subjunctive)
You need that your food has more vegetables.


By the way, you might find this thread useful.