Without reading the operating instruction carefully,workers will find it difficult to handle the machine．

单项选择题Why do some people organize parties and activities()

A. Because they have too much time.
B. Because they think it is the only way for them to express themselves.
C. Because they think it is a good way to get to know each other better.
D. Because they believe that those anniversaries have specific meanings.

单项选择题The passage is mainly about().

A. the damaged environment
B. the causes of environmental problems
C. global warming and air pollution
D. encouraging people to protect the environment