Should ( for advice ) + V ( Infinitive without S – ed – ing )
Negative : should + not = Shouldn't

Salwa has a test . She should study hard
2- Safaa has a weight problem . She shouldn’t eat much food.

Layla has a cough ? What should she do ?
She should drinl lemon with honey

Ali has a chicken pox What should he do ?

He should stay in bed