Cares play an important role in modern life, but they () also cause many problems like air pollution.

单项选择题It is essential that people () enough vitamins every day.

A. have
B. had
C. must have
D. will have

单项选择题Environmental groups intend to () the pressure until the government changes the law.

A. make up
B. pick up
C. keep up
D. bring up