Now, we know that if we do not get enough vitamins, we are at 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 disease.
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 disease. People who know they lack a particular vitamin should take vitamin supplements. Some older adults, for example, may not have enough vitamin B-twelve. 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 also is in the yellow part of eggs. Sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into vitamin A. Vitamin B-twelve is found in green leafy vegetables and other foods, like fruits. Vitamin K can be found in pork products.
In fact, for most people, a balanced diet can ensure enough of the 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 our bodies need.
【小题1】Vitamin supplements are popular with people because ________. 

Now, we know that if we do not get enough vitamins, we are at 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 disease.

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 disease. People who know they lack a particular vitamin should take vitamin supplements. Some older adults, for example, may not have enough vitamin B-twelve. 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 also is in the yellow part of eggs. Sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into vitamin A. Vitamin B-twelve is found in green leafy vegetables and other foods, like fruits. Vitamin K can be found in pork products.

In fact, for most people, a balanced diet can ensure enough of the 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 our bodies need.

1.Vitamin supplements are popular with people because ________. 

2.From the passage, we can learn that medical experts advise people _________.

3.For people who lack Vitamin B-twelve, they can eat more from _______.

A. sweet potatoes   B. pork products   C. green leafy vegetables  D. eggs

42. What would be the best title of 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.

We often talk about ourselves as if we have permanent genetic defects （缺陷） that can never be changed．“I’m impatient．” “I’m always behind．” “I always put things   21 !” You’ve surely heard them．Maybe you’ve used them to describe   22 ．

These comments may come from stories about us that have been   23  for years—often from   24  childhood．These stories may have no   25  in fact．But they can set low expectations for us．As a child, my mother said to me, “Marshall, you have no mechanical （操作机械的） skills, and you will never have any mechanical skills for the rest of your life．” How did these expectations   26  my development? I was never   27  to work on cars or be around   28 ．When I was 18, I took the US Army’s Mechanical Aptitude Test．My scores were in the bottom for the entire nation!

Six years later,   29 , I was at California University, working on my doctor’s degree．One of my professors, Dr．Bob Tannbaum, asked me to write down things I did well and things I couldn’t do．On the positive side, I   30   down, “research, writing, analysis, and speaking．” On the   31  side, I wrote, “I have no mechanical skills．”

Bob asked me how I knew I had no mechanical skills．I explained my life   32  and told him about my   33  performance on the Army test．Bob then asked, “  34  is it that you can solve   35  mathematical problems, but you can’t solve simple mechanical problems?”

Suddenly I realized that I didn’t   36  from some sort of genetic defect．I was just living out expectations that I had chosen to   37 ．At that point, it wasn’t just my family and friends who had been   38  my belief that I was mechanically hopeless．And it wasn’t just the Army test, either．I was the one who kept telling myself, “You can’t do this!” I realized that as long as I kept saying that, it was going to remain true．  39  , if we don’t treat ourselves as if we have incurable genetic defects, we can do well in almost   40  we choose．