Karamö, le prof virtuelLeçon 5 sur 20
Modal verbs: must, have to, should, may, might (les modaux)
Je sais exprimer l'obligation, l'interdiction, le conseil, la permission et la possibilité avec must, have to, should, may et might.
- 45 min
- 5 exercices corrigés
- 1 schéma
- QCM de 5 questions
À la fin de la leçon, tu sauras :
- Connaître les règles de construction des verbes modaux
- Distinguer must, have to, mustn't et don't have to
- Donner un conseil avec should
- Exprimer la permission et la possibilité avec may et might
Avant de commencer : Can et could vus en 8e et 9e, le present simple et les formes do/does/did.
1Je découvre
Au centre de santé de Télimélé, l'infirmière parle à Kadiatou, qui a de la fièvre depuis deux jours :
*« You must take these tablets three times a day. You should drink a lot of water. You mustn't go out in the sun. You may go back to school on Monday, but you might feel tired for a few days. »*
Kadiatou comprend qu'elle a des choses à faire et d'autres à éviter, mais tous ces petits mots, must, should, mustn't, may, might, la déroutent. Ils ne se conjuguent pas comme les autres verbes : pas de -s à la 3e personne, pas de do dans les questions…
Ce sont des verbes modaux. Ils ajoutent une nuance au verbe principal : obligation, conseil, interdiction, permission, possibilité. Dans la vie de tous les jours (règlement de l'école, consignes de santé, code de la route) et au BEPC, ils sont indispensables.
Comment se construisent les modaux, et quel modal choisir pour obliger, interdire, conseiller, permettre ou exprimer un doute ?
2Je comprends
1. Les règles communes des modaux
Must, should, may, might (comme can, could, will) obéissent à quatre règles :
- Ils sont invariables : pas de -s à la 3e personne. She must, jamais ~~she musts~~.
- Ils sont suivis de la base verbale sans to : You should rest, jamais ~~You should to rest~~.
- La négation se fait directement avec not : must not (mustn't), should not (shouldn't), may not, might not.
- La question se fait par inversion, sans do : Should I call the doctor? ~~Do I should…~~
Attention : have to n'est pas un vrai modal. Il se conjugue comme un verbe ordinaire : she has to, she doesn't have to, does she have to…?, she had to.
2. L'obligation : must et have to
- must : obligation ressentie par celui qui parle, ou règle écrite forte. I must finish this work tonight. Pupils must wear the school uniform.
- have to : obligation venue de l'extérieur (règlement, situation, autre personne). I have to get up at 5 because the school is far.
Must n'a pas de passé ni de futur : on utilise had to et will have to.
Yesterday, I had to walk to school. Tomorrow, you will have to come early.
3. Interdiction ou absence d'obligation : mustn't et don't have to
C'est le piège le plus célèbre :
| Forme | Sens | Exemple |
|---|---|---|
| mustn't | interdiction : il ne faut pas | You mustn't smoke in the hospital. |
| don't have to | absence d'obligation : ce n'est pas nécessaire | You don't have to wear a tie; it's optional. |
We don't have to go to school on Sunday : nous ne sommes pas obligés d'y aller (on peut, si on veut). We mustn't cheat during the exam : c'est interdit.
- C'est interdit
- Tu n'as pas le choix : tu ne le fais pas
- You mustn't cross on the red light.
- Pupils mustn't cheat.
- Ce n'est pas obligatoire
- Tu as le choix : tu fais ou pas
- You don't have to pay: it's free.
- Pupils don't have to come on Sunday.
4. Le conseil : should
should (devrait, il faudrait) donne un conseil ou une recommandation moins forte que must.
You should sleep under a mosquito net. You shouldn't eat too much sugar.
Pour demander conseil : What should I do?
On trouve aussi ought to, de même sens : You ought to rest.
5. La permission : may (et can)
may demande ou donne une permission, de façon polie ou officielle.
May I come in, sir? — Yes, you may. / No, you may not.
Pupils may use a dictionary during the test.
Entre amis, on dit plutôt can : Can I borrow your pen?
6. La possibilité : may et might
may et might expriment une possibilité : quelque chose peut arriver, mais on n'en est pas sûr.
It may rain this afternoon. (il se peut qu'il pleuve)
Alpha might come to the party, but he isn't sure. (possibilité plus faible)
On peut classer le degré de certitude :
| Certitude | Phrase |
|---|---|
| Sûr | It will rain. |
| Probable | It may rain. |
| Moins probable | It might rain. |
| Impossible | It won't rain. |
7. Tableau récapitulatif
| Modal | Fonction | Exemple |
|---|---|---|
| must | obligation forte, personnelle ou règle | I must study. |
| have to | obligation extérieure | She has to wear a uniform. |
| mustn't | interdiction | You mustn't lie. |
| don't have to | pas d'obligation | You don't have to come. |
| should | conseil | You should see a doctor. |
| may | permission polie, possibilité | May I sit here? It may rain. |
| might | possibilité faible | He might be late. |
Méthode
Pour choisir le bon modal :
- Je me demande quelle idée la phrase exprime : obligation, interdiction, absence d'obligation, conseil, permission ou possibilité.
- Obligation → must (personnelle, règle) ou have to (extérieure) ; au passé → had to.
- Interdiction → mustn't ; pas nécessaire → don't/doesn't have to.
- Conseil → should ; permission polie → may ; possibilité → may ou might.
- Je construis : modal + base verbale, sans to, sans -s ; mais have to se conjugue (has to, doesn't have to, had to).
Exemple
Complete with mustn't or don't have to.
a) You ... touch the electric wires. It's dangerous.
b) Tomorrow is a holiday: we ... get up early.
a) Toucher les fils électriques est dangereux : c'est interdit → mustn't.
b) C'est un jour férié : se lever tôt n'est pas nécessaire → don't have to.
Exemple
Give advice with should or shouldn't to Ibrahima, who often has malaria.
Il faut transformer chaque idée en conseil, avec should + base verbale.
You should sleep under a mosquito net every night.
You should remove stagnant water around the house.
You shouldn't wait before going to the health centre when you have a fever.
Exemple
Put in the past: « Fatoumata must help her mother. »
Must n'a pas de forme passée : on utilise had to.
Answer: Fatoumata had to help her mother.
3Je retiens
Je retiens
Modaux (must, should, may, might) : invariables, suivis de la base sans to, négation avec not, question par inversion.
must = obligation forte ou règle ; have to = obligation extérieure (se conjugue : has to, had to).
mustn't = interdiction ; don't have to = ce n'est pas obligatoire.
should = conseil (shouldn't = déconseillé).
may = permission polie ; may et might = possibilité (might moins probable).
Passé de must : had to ; futur : will have to.
4Erreurs fréquentes
- Ajouter to ou -s après un modal : « He must go », pas « He must to go » ni « He musts go ».
- Confondre mustn't et don't have to : « You mustn't lie » (interdit) mais « You don't have to pay » (pas obligatoire).
- Former une question avec do : « Should I wait? », pas « Do I should wait? ».
- Écrire « I musted » au passé : on dit « I had to ».
5Je m’exerce
1Exercice 1
Match each sentence with its meaning (obligation, prohibition, no obligation, advice, permission, possibility).
a) You mustn't park here.
b) You should drink more water.
c) May I use your phone?
d) We don't have to wear a uniform on Saturday.
e) Alpha might come later, but he isn't sure.
f) Drivers must have a licence.
Voir le corrigéCacher le corrigé
a) prohibition (interdiction)
b) advice (conseil)
c) permission
d) no obligation (pas d'obligation)
e) possibility (possibilité)
f) obligation
2Exercice 2
Complete with must, mustn't or don't/doesn't have to.
a) You ... cross the road without looking.
b) Children ... go to school to learn.
c) My father ... work on Sundays; he stays at home.
d) Patients ... make noise in the hospital.
e) You ... bring food; there is a canteen.
Voir le corrigéCacher le corrigé
a) You mustn't cross the road without looking.
b) Children must go to school to learn.
c) My father doesn't have to work on Sundays.
d) Patients mustn't make noise in the hospital.
e) You don't have to bring food; there is a canteen.
3Exercice 3
Give advice with should or shouldn't.
a) Hawa has a toothache. (go to the dentist)
b) Mamadou is always tired. (go to bed late)
c) Sékou wants to pass the BEPC. (revise every day)
d) Aïssatou has a cough. (drink cold drinks)
Voir le corrigéCacher le corrigé
a) She should go to the dentist.
b) He shouldn't go to bed late.
c) He should revise every day.
d) She shouldn't drink cold drinks.
4Exercice 4
Rewrite the sentences as indicated.
a) Lansana must repair his bicycle. (yesterday)
b) She has to wake up early. (negative)
c) You must wear a helmet. (question with have to)
d) Perhaps it will rain tonight. (use might)
Voir le corrigéCacher le corrigé
a) Lansana had to repair his bicycle yesterday.
b) She doesn't have to wake up early.
c) Do I have to wear a helmet?
d) It might rain tonight.
5Exercice 5
(Type BEPC) Read the school rules and answer the questions.
SCHOOL RULES — Collège of Dinguiraye
1. Pupils must arrive before 8 a.m.
2. Pupils mustn't use phones in class.
3. Pupils have to wear the school uniform from Monday to Friday.
4. Pupils may go to the library during the break.
5. Pupils should keep the classrooms clean.
a) What time must pupils arrive?
b) Can pupils use their phones in class? Justify.
c) Do pupils have to wear the uniform on Saturday? Explain.
d) Which rule is only a piece of advice?
e) Write two more rules for your school: one with must and one with mustn't.
Voir le corrigéCacher le corrigé
a) They must arrive before 8 a.m.
b) No, they can't. Rule 2 says: « Pupils mustn't use phones in class. » It is a prohibition.
c) No, they don't. Rule 3 says the uniform is compulsory only from Monday to Friday.
d) Rule 5: « Pupils should keep the classrooms clean. »
e) Example answer: Pupils must respect the teachers. Pupils mustn't write on the walls.
Cherche d’abord seul, sur ton cahier, puis ouvre le corrigé pour comparer.
6Je vérifie
Choisis une réponse pour chaque question : la correction s’affiche aussitôt.
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Leçon ajoutée par Kharandi pour compléter le programme de la classe.
