Choose the best option.
a. He musted/had to start work at six every morning when he was a postman.
b. You have to/mustn't work hard to be successful.
c. You needn't/mustn't eat those leaves. They might be poisonous.
d. I'm happy because I mustn't/needn't get up early tomorrow.
e. You don't have to/mustn't smoke in the library.
f. She hadn't to/didn't have to wear a uniform.
g. I must/have to remember to pay the phone bill.
h. Hey! You mustn't to/mustn't park there. It's private!
i. You needn't/have to drive on the left in the UK.
j. I must/must to take more exercise.​