1. Look! The light is out in her room. She ———— to bed already.

a. must go  b.had to go  c.must have gone  d.has gone

2. Our Chinese teacher is sixty-six. Oh, no. She ———— over sixty, I think.

a. is  b.mustn't be  c.can't be  d.shouldn't be

3. They hurried so that they ———— not miss thee train.

a. might  b.should  c.ought  d.could