C.her mother's advice D.her age

2. In Paragraph 3 the writer mentions her husband mainly ______.

A.to show how one communicates effectively

B.to explain the reason for his silence in a conversation

C.to give her high opinion of his communication skills

D.to give an example of those who have the power of quiet

3. By "I had to look further", the writer means she had to ______.

A.look into the future in order to succeed in practicing the power of quiet

B.try harder to prevent herself from talking too much

C.find out other reasons why she should talk less

D.survey people in other areas who talk little

Think about vitamin D when you're catching up on summer rays. It's sometimes called the "sunshine vitamin" because it's produced in your skin in response to sunlight. Vitamin D is a fat-soluble (脂溶性的) vitamin in a family of compounds that includes vitamins D-1, D-2, and D-3. It can affect as many as 2,000 genes in the body.

Vitamin D has several important functions. Perhaps the most vital are regulating the absorption of calcium and phosphorous(磷), and promoting normal immune system function. Getting enough vitamin D is important for normal growth and development of bones and teeth, as well as improving resistance against certain diseases.

In addition to its primary benefits, research suggests that vitamin D may also play a role in:

● reducing your risk of multiple sclerosis(多发性硬化), according to a 2006 study published in the Journal of the American Medical Association

● decreasing your chance of developing heart disease, according to 2008 findings published in Circulation

● helping to reduce your possibility of developing the flu, according to 2010 research published in the American Journal of Clinical Nutrition

● regulating mood and warding off depression

● losing weight or preventing heart disease

How do you get it? Your body produces vitamin D naturally when it is directly exposed to sunlight. A little can go a long way. All you need is 10 minutes a day of midday, pre-sunscreen sun exposure, especially if you have fair skin. Besides getting vitamin D through sunlight, you can also get it through certain foods and supplements to ensure adequate levels of the vitamin in your blood.

4. Why is Vitamin D sometimes called "Sunshine Vitamin"?

A.Because it is produced in your skin reacting to sunlight.

B.Because it is named a fat-soluble vitamin.

C.Because it is produced with enough sunshine.

D.Because it is like sunshine in summer.