English Grammar: Modal Verbs Can Must Should May – 2nd Year Secondary – Algeria

Modal Verbs: Can, Must, Should, May

Modal verbs are auxiliary verbs that express ability, permission, obligation, possibility, or advice. They never change form and are followed by the base verb.

Can

Use: ability, permission, possibility.
Ex: I can swim (ability). You can go now (permission). It can be dangerous (possibility).

Must

Use: obligation, necessity, strong advice.
Ex: You must wear a seatbelt (obligation). Students must respect the rules (necessity).

Should

Use: advice, recommendation, suggestion.
Ex: You should study harder (advice). We should help others (recommendation).

May

Use: permission (formal), possibility.
Ex: May I come in? (permission). It may rain today (possibility).

Negative Forms

• Cannot / Can’t: I cannot drive a car (absence of ability).
• Must not / Mustn’t: You mustn’t smoke here (prohibition).
• Should not / Shouldn’t: You shouldn’t eat too much sugar (advice against).
• May not: You may not enter without permission (refusal of permission).

Examples

Can you speak Arabic? Yes, I can. You must finish your homework before watching TV. You should drink more water. May I use your phone?

Exercises

1. Complete with can/must/should/may: “You ___ brush your teeth twice a day. ___ I open the window? Students ___ respect their teachers.”
2. Choose the correct modal: “You (must/should) see a doctor – you look sick. I (can/may) ride a bicycle.”
3. Rewrite using the correct modal: “It is necessary to wear a helmet.” → “You ___ wear a helmet.”

For more English lessons, check Present Simple Tense and Comparative and Superlative Adjectives.