Now, we know that if we do not get enough vitamins, we are at the risk of developing a number of diseases. As a result, vitamin supplements( 补品 ), though expensive, are popular with people who worry that they are not getting enough vitamins from the foods they eat. But contrary to what many people think, medical experts have found little evidence that most supplements do anything to improve health or protect against diseases. In fact, medical experts warn that taking too many of some vitamins can be harmful. For example, too much vitamin E can cause bleeding. People should discuss what vitamins they take with their doctors, as some vitamins can produce harmful side effects when mixed with medicines. Experts, however, do say that sometimes vitamins can help prevent diseases. People who know they lack a particular vitamin should take vitamin supplements. Some older adults, for example, may not have enough vitamin B 12 .This is because, as people get older, their body loses its ability to take it from foods. Also, people who spend much time inside may need some extra vitamin D as the skin makes this vitamin from sunlight. Different vitamins are found in different foods. Vitamin A is found in fish liver oil.It's also in the yellow part of eggs. Sweet potatoes, carrots and other darkly coloured fruit and vegetables contain substances that the body can change into vitamin A . Vitamin B 12 is found in green leafy vegetables and other foods, like fruit. Vitamin K can be found in pork products. In fact, for most people, a balanced diet can ensure enough vitamins our bodies need. So, it is important for us to eat a mixture of foods every day to ensure that we get enough vitamins. 1 . What is probably talked about before this passage?_____ A . How many vitamins a person's body needs. B . How many vitamins some foods contain. C . The benefits that vitamins bring to our health. D . What people should do to stay healthy. 2 . From the passage, we can learn that medical experts advise people ________ . A . never to take any vitamin supplements B . to depend only on foods for their vitamins C . not to take any vitamins together with medicines D . to consult their doctors before taking vitamin supplements 3 . What would be the best title for the passage?______ A . Getting enough vitamins through a balanced diet B . Vitamin supplements do harm to our health C . Vitamins are important to our health D . Lacking vitamins can cause many diseases