Mum, why do I have to wash hands so many times a day?
For your health, you______be too careful.( )
A.can'tB.shouldn'tC.mustn'tD.needn't
He go to bed until he his homework.
—I don’t know when ______ tomorrow.—I will call you as soon as he ______.
——Excuse me. Is it my turn now? ——Not yet. Please wait on the chair ______your name is called.
I was surfing the Internet my brother was doing his homework.
She has studied in this school she was seven years old.