La obligación: tener que, hay que, deber
English piles 'have to', 'must', 'need to' and 'should' into more or less one heap. Spanish splits the job three ways and keeps the seams visible: tener que is the obligation with your name on it, hay que is the rule that points at nobody, and deber is the one with a conscience. Sitting alongside them are poder and querer, which behave the same way structurally. All five are followed by a plain infinitive — the only question is which ones need a que first.
TENER QUE — the obligation with your name on it
Conjugate tener, add que, then a plain infinitive. That is the whole machine, and it is the one you will reach for a dozen times a day: Tengo que estudiar. Tienes que comer. Tenemos que trabajar. The five rows are yo tengo que, tú tienes que, él tiene que, nosotros tenemos que, ustedes tienen que — and that last row does double duty, because ustedes tienen que and ellos tienen que are the same three words. Plural 'you' is never a decision here: your cousins, your classmates and your boss all get ustedes tienen que. The que in this construction is welded on. It is not the que that means 'that', it carries no meaning of its own, and dropping it breaks the sentence. One thing English speakers get backwards: No tengo que trabajar el domingo means the obligation is gone — I'm free — not that I am forbidden to work. For 'I mustn't' you want No debo.
HAY QUE — the rule nobody signed
hay + que + infinitive, and nothing in it ever moves: no subject, no conjugation, no agreement, one shape forever. Hay que estudiar. Hay que respetar las reglas. Hay que caminar rápido. You already met hay back in lesson 5 as 'there is / there are'; this is the same little word doing a second job. Because there is no subject, nobody is being told off, and that is exactly why it is everywhere. Tienes que lavarte las manos puts a finger on one person's chest. Hay que lavarse las manos simply states how things are done in this house. Kitchens, classrooms, clinics and street signs across the region run on hay que, and so does most polite advice between adults. English covers the same ground with 'you have to', 'one must', 'it's necessary to' and a shrug; Spanish has one shape for all of them.
DEBER — conscience, and money
deber is an ordinary regular -er verb — debo, debes, debe, debemos, deben — and it takes the infinitive directly, with nothing in between. Debo decir la verdad. Debes ayudar a tu mamá. Ustedes deben estudiar. Where tener que is about your calendar, deber is about what is right, which is why No debo trabajar el domingo lands as 'I mustn't', while No tengo que trabajar el domingo is the happy one that means 'I don't have to'. Two more things live inside this verb. First, it is also the everyday verb for owing: Te debo cien pesos. ¿Cuánto te debo? is what you ask when it is time to pay. Second, deber de + infinitive is the guess rather than the duty: Debe de estar en el mercado means she's probably at the market. In careful writing that little de is the whole difference; in ordinary speech across the region it often drops out and the tone carries it. The softer English 'should', the one that advises instead of commanding, is debería — it needs the conditional and waits for B1.
The que trap
Two of the five carry que and three of them do not, and mixing that up is the single most common mistake at this stage. tener que and hay que cannot live without it. deber, poder and querer take the infinitive bare: debo que ayudar, puedo que ir and quiero que comer are all wrong, every time. The fix is rhythm, not memorization — say the five out loud with the same infinitive until the shape of each one is in your mouth: tengo que ir, hay que ir, debo ir, puedo ir, quiero ir.
PODER — can, may, and asking a stranger for help
poder breaks its stem: the o becomes ue in four rows and stays put in the fifth. yo puedo, tú puedes, él puede, nosotros podemos, ustedes pueden. Read that ladder twice, because podemos is the odd one out and it is odd in exactly the same way in every stem-changing verb in the present tense — the nosotros row is always the one that keeps the original vowel. Puedo hablar español. ¿Puedes venir el sábado? No puedo on its own is a complete and perfectly polite refusal. Beyond ability, poder is how you ask permission and how you ask for a favor. At a doorway you will hear ¿Se puede? — may I come in — answered with Pase no más or Claro que sí. With a stranger, an official, or anyone noticeably older, the request goes in usted: ¿Me puede ayudar, por favor? With a friend it relaxes to ¿Me puedes ayudar? And a diminutive softens it another notch: ¿Me ayuda tantito? is what you would actually hear in Mexico, where tantito means 'just a bit' and is doing pure politeness work.
QUERER — wanting, and how not to sound blunt
querer changes its stem too, e into ie, with nosotros again standing aside: yo quiero, tú quieres, él quiere, nosotros queremos, ustedes quieren. Then an infinitive, no que: Quiero comer. Queremos aprender español. ¿Quieres café? You have crossed this verb twice already — as 'to want' in lesson 1, and in lesson 13 with a person after it, where it turns into the everyday word for love. Ordering and asking is where register matters. A flat Quiero un café is perfectly grammatical and lands a little bare in most of Latin America. What people actually say adds something small: Quiero un cafecito, por favor. or ¿Me da un café, por favor? The -ito on cafecito is not claiming the coffee is small — it is carrying the politeness, and that habit is one of the most audible markers of the whole variety.
Saying yes, saying no, and buying time
Accepting is short: Claro. Claro que sí. Por supuesto. Está bien. For plain 'OK' the region reaches for bueno, está bien, dale in the Southern Cone, órale in Mexico. Declining is shorter still — No puedo needs nothing after it, though a reason is friendlier: No puedo, estoy muy ocupado. And then there is the great soft answer, ahorita, which you met in lesson 12: Ahorita lo hago can mean I'm on it, or give me a minute, or — depending on the country, the speaker and the tone — sometime before the day is out. In Mexico it usually buys a little time; in the Andes and the Caribbean it leans closer to right now. When you need to be unambiguous, ya voy is the one that means you are actually moving.
