“I musn't run away.”
“You musn't be afraid to dream a little bigger, darling.”
“But he remembered that even if she did box his ears, he musn't box hers again, for she was a girl, and all that boys must do, if girls are rude, is to go away and leave them.”
“You musn't neglect your education in favor of your studies.”
“You're only given a spark of madness. You musn't lose it.”
“We musn't let anything happen to Piggy, must we?”