题目内容
（请给出正确答案）
提问人：网友dongwen_wen
发布时间：2022-01-06
[主观题]
【B18】A．thereforeB．howeverC．whileD．but
【B18】
A．therefore
B．however
C．while
D．but
简答题官方参考答案
（由简答题聘请的专业题库老师提供的解答）
查看官方参考答案
Do you know your cholesterol level？ Many people don't. A high level of cholesterol in the blood is an important risk factor for heart disease.
Some people say that the danger of heart disease is exaggerated. However, heart disease is a main cause of death in developed countries. Every year more than one million Americans have heart attacks, and half of them die. People with heart disease suffer chest pains that make simple activities, such as walking, shaving, or taking a shower, difficult.
Research has proven that cholesterol levels are connected with heart disease. One project in Massachusetts has studied the same group of men and women since 1948. The researchers have found that the people who have high levels of cholesterol have more heart attacks.
A natural substance in the blood, cholesterol comes from the liver. The amount of cholesterol is affected by diet and by physical qualities we inherit from our parents. One kind of cholesterol sticks fat to the walls of arteries, making them smaller and finally blocking them. It produces a condition called "hardening of the arteries," which causes heart attacks. With tiny cameras, doctors can see blood circulating through the heart valves. Angiograms(血管造影照片) are x-rays of the heart arteries. They show fat deposits and blockages caused by high cholesterol.
Heart disease begins in children as young as 3 years old. It occurs earlier in boys than in girls. Nearly half of teenagers have some fat deposits on their artery walls. Heart disease develops faster if we have high cholesterol levels and also smoke.
What is a safe level of cholesterol？ Adults have a high risk of heart attack if their cholesterol level is above 240 milligrams per deciliter(1/10公升) of blood. Below 200 is better. In the Massachusetts study, no one with a cholesterol level below 150 has ever had a heart attack. However, about half of American adults have cholesterol levels above 200. To lower our cholesterol level, we must change our eating habits. Anything that comes from an animal is high in fat and high in cholesterol. The American Heart Association National Cholesterol Education Program says that fat should be no more than 30 percent of our diet. Blood cholesterol levels start to fall after 2 to 3 weeks of following a low-cholesterol, low-fat diet. Dietary changes alone can result in a 10 percent reduction of the average person's cholesterol level. Aerobic exercise helps, too. Artery blockage can be reduced by as much as 40 percent through changes in diet and amount of exercise.
We must educate everyone, including children in elementary schools. We must teach them responsibility for their health through classes in nutrition and aerobic exercise. For example, the smart snack is fruit. Children must be served fruit in the school cafeteria, along with low-fat meals. Schools must send recipes home wish the children. Parents must include children in planning and preparing meals and shopping for food.
Adults, including persons over the age of sixty five, can lower their cholesterol by 30 or 40 percent. It is never too late to change. One man began his health program when he was seventy three. By the time he was seventy-seven, he had lowered his arterial blockage from 50 percent to 13 percent and his cholesterol from 320 to 145 without drugs. He went on a vegetarian diet with only 10 percent fat, plus programs to reduce stress and get more exercise.
A low-cholesterol diet that cuts out most animal products and high-fat vegetables may be un familiar to people. The Heart Association says to use no added fat of any kind. Don't fry food in oil. Cook it in water, vinegar, or vegetable water. Learn about grains and vegetables. Avoid egg yolks(the yellow part of the egg). Eat potatoes, beans, low fat vegetables, and fruit. People of ten complain about low-fat di
A．Y
B．N
C．NG
