=>
I/
1. B
2. D
II/
1. Nam is taken to the zoo by his parents every month.
2. Billions of cans are thrown away every year.
III/
1. The housework must be done by Lan tomorrow morning.
2. Your bike can be repaired by Nam right now.
IV/
1. I was very delighted to pass the final exams.
2. We were sorry that we heard about your father’s illness.
3. He was very surprised to get your letter.
4. She was happy that she received a lot of birthday presents.