Over 2 million Canadians have diabetes. It is the leading cause of
blindness in North Americans under 65 years of age. Diabetes is a condition
where the body either cannot produce enough insulin (胰岛素) or cannot respond
properly to insulin. Insulin is important because it moves glucose (葡萄糖), a
simple sugar, into the body's cells from the blood. The food people eat provides
the body with glucose, which is used by the cells as a source of energy. If
insulin isn't available or doesn't work correctly to move glucose from the blood
into the cells, glucose will stay in the blood, leading to high blood sugar
levels. High blood sugar levels damage the blood vessels,
including the tiny blood vessels in the eye. This leads to an eye disease known
as diabetic retinopathy (糖尿病型视网膜病). The retina (视网膜) is an area at the back of
the eye that changes light into nerve signals. With diabetic retinopathy, some
blood vessels in the retina are lost, and some of the other blood vessels begin
to "leak" blood. This causes the retina to swell and gradually cuts off its
supply of oxygen and nutrients (滋养物). Eventually, the retina starts to grow new
blood vessels to replace the damaged ones. Unfortunately, these new vessels are
not as strong as the old ones. They are more likely to break, causing bleeding
in the eye. At first, people with diabetic retinopathy will not
notice any symptoms. As the disease gets worse, they may notice blurred (模糊的)
vision, black spots or flashing lights. As time goes on, it can progress to
blindness. Everyone with diabetes is at risk for diabetic
retinopathy, and the risk increases the longer you've had diabetes.
Fortunately, you can reduce your risk if you do not have diabetes, but
think you may be at risk for this condition. Visit your doctor to be screened
for diabetes. If you do have diabetes: have frequent eye check-ups.
Make sure that you monitor your blood sugar frequently and use your
medications as recommended by your doctor. There is evidence to show that
keeping your blood sugar under tight control can slow down eye damage. If you
have high blood pressure, follow your recommended diet and medications to keep
it under control. If you are not sure whether you have high blood pressure, or
whether your blood pressure is under control, discuss this with your
doctor.
单选题
Glucose cannot be turned into energy in the body ______.
单选题
The word "its" in the second paragraph refers to ______.
A. the nerve's
B. the blood's
C. the eye's
D. the retina's
【正确答案】
D
【答案解析】[解析] 在这个句子中，its显然指的是retina's一词。
单选题
With diabetic retinopathy, the damaged blood vessels in the retina
______.
A. are stronger than what they used to be
B. cannot be properly replaced
C. are more likely to break than the new ones
D. may return to normal again
【正确答案】
B
【答案解析】[解析] 利用题干关键词定位到文章第二段的最后三句话“Eventually, the retina starts to grow new blood vessels to replace the damaged ones. Unfortunately, these new vessels are not as strong as the old ones. They are more likely to break, causing bleeding in the eye.”即“最终，视网膜开始长出新的血管来替换受损的血管。不幸的是，这些新的血管不像老血管那么有力，更可能破裂，从而引起眼部的出血。”由此不难看出，患有糖尿病的病人视网膜血管损坏后，新生的血管不像原来的血管那样好用。
单选题
The worst eye damage induced by diabetes is ______.
A. blurred vision
B. black spots
C. blindness
D. flashing lights
【正确答案】
C
【答案解析】[解析] 利用题干关键词定位到文章第三段，可知糖尿病所能造成的最坏的眼损伤是失明。
单选题
To slow down eye damage, people with diabetes should try to ______.