题目内容：

The federal school lunch program for 30 million low-income children was created more than half a century ago to combat malnutrition(营养不良). A breakfast program was added during the 1960s, and both attempted to improve the nutritional value of food served at school.

More must be done to fight the childhood obesity(肥胖) epidemic, which has caused a frightening peak in weight-related disorders like diabetes, high-blood pressure and heart disease among young people. The place to start is schools, where junk food sold outside the federal meals program—through snack bars and vending machines—has pretty much canceled out the benefits of all those efforts.

Federal rules that govern the sales of these harmful foods at school are limited and have not been updated for nearly 40 years. Until new regulations are written, children who are served healthy meals in the school cafeteria will continue to buy candy drinks and high sodium(钠) snacks elsewhere in school.

Many states’ school districts have taken positive steps, but others are likely to resist, especially districts that sell junk food to finance athletic program extracurricular activities, and even copier expenses.

Those districts should take note of a study released in 2009 in West Virginia showing that the budgetary costs of switching from sodas to healthy drinks such as fruit juice, milk, and water were very little. Even if the switch costs money, so be it. The school should not be trading their students’ health to buy office supplies.

Over the last five decades, the obesity rates for adolescents have tripled. Unless there is decisive action, weight and inactivity-related disorders will bother a steady larger proportion of the work force and replace smoking as the leading cause of premature death.

1.According to this passage, ______ are to blame for the childhood obesity.

A. weight-related disorders

B. high calorie snacks

C. parents’ bad habits

D. unhealthy lunches and breakfast

2.Which is the main idea of Paragraph 3?

A. Federal governments deserve high praise for their school lunch program.

B. New regulations are badly in need of updating.

C. Children should be forbidden to buy snacks in school.

D. Federal rules encourage snacks outside the school program.

3.The passage is concerned mainly with ______.

A. Malnutrition in low-income children

B. The federal school lunch program

C. obesity at school

D. the nutritional value of food served at school

4.The tone of this passage is ______.

A. negative          B. indifferent

C. optimistic         D. ironic