Give some materials, including: environmental pollution, national physique, national fitness and so on.

1, through the given materials, explain the causes of frequent environmental pollution accidents; (200 words)

2. Write an opinion on further strengthening the national fitness work from the perspective of government workers, and seek reasonable and feasible suggestions; (300 words)

3. Explain the relationship among economic development, environmental protection and health protection according to the given materials; (300 words)

4. Write an argumentative essay with "health is a big issue related to national prosperity, social harmony and family happiness" as the main content. (800- 1000 words)