For much of the world, vegetarianism (素食主义) is largely a matter of economics: Meat costs a lot more than beans or rice, so meat becomes a special-occasion dish. Even where meat is more plentiful, it’s still used in control, and it often provides a side note to a meal rather than taking center stage.
In countries like the United States where meat is not as expensive, though, people choose to be vegetarians for reasons other than cost. Parental preferences(父母亲的偏爱), religious or other beliefs, and health problems are among the most common reasons for choosing to be a vegetarian. Many people choose a vegetarian diet out of concern over animal rights or the environment. And lots of people have more than one reason for choosing vegetarianism.
Different people follow different forms of vegetarianism. A true vegetarian eats no meat at all, including chicken and fish. A lactoovo(乳制品)  vegetarian eats dairy products  and eggs, but keeps out meat, fish, and chicken. It follows, then, that a lacto(乳，乳汁) vegetarian eats dairy products but not eggs, and an ovo （蛋，鸡蛋） vegetarian eats eggs but not dairy products.
A stricter form of vegetarianism is veganism. Not only are eggs and dairy products excluded (排除) from a vegan diet, so are animal products like honey. Some macrobiotic (养生的) diets fall into the vegan category. Macrobiotic diets limit not only animal products but also refined（经过提炼的） and processed foods, foods with preservatives, and foods that contain caffeine or other stimulants (刺激物).
Following a macrobiotic or vegan diet could lead to nutritional deficiencies (营养不足) in some people. Teens need to be sure their diets include enough nutrients to fuel growth, particularly protein and calcium (钙). If you’re interested in following a vegan or macrobiotic diet it’s a good idea to talk to a registered dietitian（营养学家）. He or she can help you design meal plans that include enough nutrients.
The underlined sentence in the first paragraph probably means ______.

A．there is usually a note beside the meat in a meal

B．meat often attracts people’s attention in a meal

C．meat is served only a small amount in a meal

D．meat should play an important part in a meal

. Which of the following is NOT the reason for Americans being vegetarians?

A．They are environmentally friendly.

B．They are concerned about the rights of animals.

C．They worry about their own health.

D．They can’t afford to buy meat.

A vegan diet will include ______.

A．neither animal products nor diary products

B．diary products but no eggs

C．animal products like honey

D．processed food

. According to the passage, the author would probably think that ______.

A．all the people should become vegetarians

B．teens should be careful to be vegetarians

C．vegetarianism is not a good thing for the world

D．vegetarianism can make a country develop faster