Exercicis de modals d'obligació i consell — Anglès 3r ESO

'Drivers must stop at a red light.' És una obligació (norma de trànsit).

'You mustn't tell anyone.' És una prohibició (no ho pots dir).

'You shouldn't watch another episode.' És un consell negatiu (no és bona idea).

És una prohibició: mustn't.
You mustn't use your phone during the exam.

És un consell afirmatiu: should.
You look ill. You should see a doctor.

She és tercera persona del singular: has to.
She has to get up early on weekdays.

Negativa de should: shouldn't + infinitiu sense to.
You shouldn't drink coffee at night.

El passat de have to és had to, i no canvia amb el subjecte.
Yesterday I had to stay at home.

Model de resposta: You should go to bed earlier. / You shouldn't use your phone in bed.
Should + infinitiu sense to.

(a) Obligació (must).
(b) Consell (shouldn't).
(c) Prohibició (mustn't).

'She must finish her homework.' Els modals no porten -s a la tercera persona.

'You don't have to bring food; lunch is included.' 'don't have to' = no és necessari.

'Do they have to pay in advance?' 'have to' fa la pregunta amb 'do/does'.

'Should I wear a coat?' Els modals fan la pregunta invertint amb el subjecte, sense 'do'.

'You should study more.' Després de 'should' va l'infinitiu sense 'to'.

No és necessari, però tampoc està prohibit: don't have to.
You don't have to tell Sam. He already knows.

Passat negatiu de have to: didn't have to + infinitiu.
We didn't have to get up early yesterday because it was a holiday.

Must no es nega amb do. La prohibició és mustn't.
You mustn't run in the corridors.

Una necessitat es pot expressar amb have to.
We have to wear a helmet.

Pregunta en passat: did + subjecte + have to + infinitiu.
Did Marc have to wait for an hour?

(a) You mustn't talk loudly (prohibició).
(b) You don't have to pay (no cal pagar).
(c) You must wear a helmet (obligació).

(a) mustn't (prohibit per llei).
(b) don't have to (no és necessari).
(c) shouldn't (consell).

'You mustn't be late for the interview.' Arribar tard no està permès (prohibició), no és una qüestió de 'no cal'.

'You don't have to finish today; you can finish tomorrow.' No és necessari acabar avui (hi ha alternativa), per tant 'don't have to'.

Error 1: no hi ha obligació d'anar a l'escola, però tampoc està prohibit: we don't have to go to school.
Error 2: després de should no va to: You should relax.

Model de resposta:
You should make a study plan.
You shouldn't study all night.
You should take short breaks.
You must sleep at least eight hours before the exam.
Es valora la diferència entre consell (should) i obligació (must).

Ordre: mustn't (prohibició), don't have to (no és necessari), must (obligació).
In my school you mustn't use your phone in class, but you don't have to wear a uniform on Fridays, and you must be on time.

(a) You don't have to bring a gift.
(b) You mustn't take photos here.

(a) Fals: mustn't és prohibició; don't have to vol dir que no cal.
(b) Fals: should és un consell i must és una obligació.
(c) Cert: must no té passat, i s'usa had to.

Model de resposta:
You should plan your week. You shouldn't use your phone for hours in the evening. You have to do your homework before dinner, but you don't have to do it all in one day.
Es valora l'ús correcte de should, shouldn't, have to i don't have to.