His failing in the exam ________ us because he was always an outstanding student.
The number of the students is_________ rapidly in our school.
During your English study, you will______ many difficulties.
Hiking by oneself can be _______ and good for health. It may also be good for_______ training.
Though _______ abroad for years, many Chinese still ______ the traditional customs.
In winter, the town is often _____ by snow.