"What we have to watch?" Is not a full sentence, but merely a subordinate clause that we use within a longer sentence: “I wonder what we have to watch” or “That is what we have to watch.” If your intention is to ask a direct question, we need to use inversion: “What do we have to watch?” Although the meaning of “have to” is modal, English does not consider it to be a “modal verb” in terms of the grammar structure. English modal verbs are defective, that is, they have no infinitive or participles and do not take S in the present tense 3rd person singular. One such verb is “must” (which also lacks a past tense) — it can have the same meaning as “have to,” although “must” is usually used for expressing a high degree of certainty, rather than necessity. The verb “(to) need” has a similar meaning as “to have to” and is likewise not classified as modal in American English. However, it can still sometimes be considered modal in British English. Another such “semimodal verb” is “ought” (originally the past subjunctive of “to owe”). The list of “modal verbs” is actually quite short in English. Here are the main ones, off the top of my head: can, could, may, might, must, will, would, shall, should EDIT: I should point out that I've assumed your statement was about a requirement to watch something, since you asked if "have" was modal. A completely different interpretation would be that "have" refers to your having possession of watchable media. The structure would be exactly the same, and it would definitely not be modal.

Don't forget to add "do" to questions in English. It would be... "What do we have to watch?" This grammar rule is tricky to explain, because I (and all native speakers) use it without thinking about the grammatical rules. But let me give it a shot - When you ask a question, and the verb is any verb other than "to be", always include "Do/Does/Did" in the PRESENT TENSE ONLY and BEFORE THAT VERB. Examples: "What DO we have to watch?" " When DOES your plane leave?" Now, we're talking about English, so let's explore the exceptions... "What ABOUT the others?" (Still a question, but there is no verb) When WILL he get here?" (Future tense, so DO is not used) What IS your name (The verb is TO BE so DO is not used) Next... TO HAVE is also a modal verb. Normally it means to possess or hold something, but we also use it as a modal verb to set off a perfect tense or certain past tenses (if that was too much grammar lingo, let me know and I'll explain it better). So... in conclusion. The sentence "Which movies to watch do we have" and similar constructions are technically correct, but no one would say that. I hope this helps:) If anything is unclear, just leave a comment and I'll take another shot at it.

Yes, I think the way you used "have to" is fine. I believe you are asking whether it's okay to use "have to" in your phrase when it might be taken in the wrong sense of "must/should watch" instead of "have available so we can watch". A common example of such usage is "That's all I have to say", which is often said after making a (formal) speech to mean "That's all I could think of saying" or "That's all I intend to say". I doubt anyone would take issue with that statement saying it might be interpreted as "That's all I must/should say". The context usually makes it clear in what sense the phrase is used.