Modals | 1st Year Bac Lesson

A modal verb goes before a base verb (no -s, no -ing, no -ed) to add meaning like ability, obligation, advice, or possibility. This unit focuses on modals used for health and advice.

MODAL + BASE VERB
“You should rest.” (not “should resting” or “should rests”)

Use “should” to give advice or say what is a good idea.

“You should drink more water.”
“You shouldn’t skip meals.”

“Must” shows something is very necessary. “Mustn’t” shows something is forbidden — don’t do it.

“You must take this medicine every day.” (very necessary)
“You mustn’t smoke here.” (it’s forbidden)

“Have to” is similar to “must” but often shows a rule from outside (like a doctor’s order), not a personal feeling. “Don’t have to” means it’s not necessary — but it’s still allowed.

“I have to see the doctor tomorrow.” (it’s necessary — an appointment)
“You don’t have to take painkillers if the pain is mild.” (not necessary, but okay if you want to)

“Can” shows ability (what someone is able to do) or permission (what’s allowed).

“She can walk again after the surgery.” (ability)
“You can’t eat before this test.” (not allowed)

Use “might” or “may” when something is possible, but not certain.

“You might feel a little dizzy after the injection.”
“The doctor may want to run more tests.”

Never add “to” directly after a modal verb, and never add -s, -ing, or -ed to the verb that follows.

❌ “You should to rest.”
✅ “You should rest.”
❌ “She can swims well.”
✅ “She can swim well.”