Obligation vs. Task Possession
In European Portuguese, there is a normative difference between ter de and ter que. While native speakers sometimes mix them up in informal speech, formal grammar separates strict obligations from possessing tasks to do.
Use ter de + infinitive to express a strict obligation ("must" or "have to").
| The head housekeeper was going to speak with me, because I have to clean the carpet. | A governanta ia falar comigo, porque tenho de limpar a alcatifa. |
| The head housekeeper wants to speak with you, because you have to disinfect the doorknob. | A governanta quer falar consigo, porque o senhor tem de desinfetar a maçaneta. |
Use ter que + infinitive for possessing things, chores, or tasks to complete ("having [something] to do"). This almost always follows quantity words or indefinite pronouns like muito (a lot), pouco (little), algo (something), or nada (nothing).
| The new room attendant has a lot to do and little to disinfect. | A nova camareira tem muito que fazer e pouco que desinfetar. |
| Do you have something to store in the wardrobe, or do you no longer have to open it? | Tens algo que guardar no roupeiro, ou já não o tens de abrir? |
Without a specific quantity word, use ter o que. Notice how the following sentence contrasts task possession (ter o que) with a resulting obligation (ter de):
| They have things to restock, so they have to open the minibar. | Eles têm o que abastecer, por isso têm de abrir o minibar. |
This contrast is especially clear in the negative. Not having to do something (lack of obligation) uses não ter de. Not having anything to do (lack of tasks) uses não ter nada que or não ter o que.
| You do not have to vacuum the carpet, because you do not have anything to vacuum today. | Vocês não têm de aspirar a alcatifa, porque não têm o que aspirar hoje. |
| I was going to use the mop, but after all I have nothing to clean. | Ia usar a esfregona, mas afinal não tenho nada que limpar. |