46.The countryside is most beautiful in autumn. (Cleft Sentence)
47.It is Tet that is celebrated as the greatest occasion in a year by Vietnamese people.
48.The teacher was asked for his explanation for the problem by the students
49.Nam was prevented from going to school by the thick fog
50.They think that I should do volunteer work
51.We must do well at school
52.These instructions could be understood by anyone with the smallest intelligence
53.This rumor must have been started by our opponents
54. You mustn't use your cell phone in class
55.Tom should see the doctor because of his terrible cough
