用方框中所给短语的适当形式填空:

Jay Chou ____________________ music and has written and sung a lot of popular songs such as Blue and White Porcelain《青花瓷》and East Wind Broken《东风破》.
Studies show that people ____________________ suffer from back problems if they always sit before computer screens for long hours.
____________________, senior school students should take part in all kinds of after-school
activities in their spare time.
It is essential for students to ____________________ classes at school.
Oliver Twist __________ child poverty _______________ the public, and for this reason alone it is a very important novel.
Shocked by the scene, the warden who was strong and healthy had to ____________________ the wall for support.
It is the protection for the trees that really matters, ___________________ how many trees are planted every year.
There is a widely held belief that the tourism is ____________________because of the economic recession（衰退）.
China is working ____________________ the other countries in international affairs.
China ____________________ the giant panda.