阅读理解。 Nowadays, in the United States and other western countries, some teens are choosing to become vegetarians.  That is, they choose not to eat meat.  There are many types of vegetarians, some of whom don't even eat animal products such as milk, eggs, or yogurt. Having balanced meals is very important, especially for teens who are growing up. So why are they becoming vegetarians? Well, they choose to become vegetarians for different reasons. The most popular reason is just wanting to be healthier. I decided to become a vegetarian when l was 10 years old,  and it was much easier than you might think.  But as a vegetarian,I have had a difficult time getting the proper  nutrition. Most doctors and scientists say that being a vegetarian is very healthy, but many people aren't choosing the correct food to supplement the protein in meat. If you're thinking about becoming a vegetarian, make sure that you pay attention to your diet very carefully.  And of course, pay special attention to your health when doing so. Being a vegetarian isn't for everyone, so don't be discouraged if you can't give up hamburgers and meat dumplings! Vegetables play an important role in people's daily meals, so even if you are not a vegetarian, they are still good for you. 1. Some teens choose to become vegetarians mainly because_______. A.  they have no meat to eat B.  they want to keep healthy C.  they only like vegetables D.  they can grow up quickly 2. If you decide to become a vegetarian, you should _______. A.  eat only vegetables B.  do more exercise C.  become more careful in everything D. get the proper nutrition 3.  Which is the best title of this passage? A. Becoming a vegetarian B.  Eating no meat C.  Paying attention to your diet carefully D.  Protecting animals