Don't run!
Be careful. / Watch out.
Don't turn left
Speak in English!
Don't eat!
Be quiet!
Don't shout!
Turn off the light!
Wash your hands!
Don't park
Don't stand up. / Stay there
Do your homework!
Clean your room!
Turn right
Open your book
Close your book
Don't use your phone!
Open/Close the window!
Don't take pictures!
Take this medicine.