胺类药物的一般特性不正确的是（） A.具有芳伯氨基的重氮化反应、重氮化-偶合反应以及

从纬度位置与海陆位置看，世界人口稠密地区主要分布在（　　）

A．中低纬的内陆地区

B．中高纬的内陆地区

C．中低纬的沿海地区

D．中高纬的沿海地区

阅读理解。

     Songs that make our hearts happy can make them stronger too, US researchers reported on Tuesday.

     They found that when people listened to their favorite music, their blood vessels (血管) dilated in much

the same way as when they are laughing, or taking blood medications (药物).

     "We have a pretty impressive effect," said Dr Michael Miller, director of preventive cardiology (心脏病学)

at the University of Maryland Medical Center in Baltimore.

     "Blood vessel diameter improved," he said. "The vessel opened up pretty significantly. You can see the

vessels opening up with other activities such as exercise." A similar effect is seen with drugs such as statins.

     When blood vessels open up more, blood flows more smoothly and is less likely to form the clots (凝块)

that cause heart attacks and strokes. "We are not saying to stop your stations or not to exercise but rather to

add this to an overall program of heart health," said Miller, who presented his findings to a meeting of the

American Heart Association in New Orleans.

     Miller's team tested 10 healthy, non-smoking men and women, who were told to bring their favorite music.

They spent half an hour listening to the recordings and half an hour listening to music they said made them feel

anxious while the researchers did ultrasound (超声波) tests designed to show blood vessel function.

     Compared to their normal baseline measurements, blood vessel diameter increased 26 percent on average

when the volunteers heard their joyful music. Listening to music they disliked-in most cases in this group heavy

metal-blood vessels narrowed by six percent, Miller said.

     Miller said he came up with the idea after discovering that laughter caused blood to literally flow more

smoothly. "I asked myself what other things make us feel real good, besides calories from dark chocolate of

course. Music came to mind.... It makes me feel really good," he said.

     Most of the volunteers chose country music but Miller said the style is not so important rather than what

pleases each individual.

1. The underlined word dilate (in paragraph 2) is closest in meaning to "_____".

A. widen

B. move

C. change

D. increase

2. According to the passage, which of the following will NOT cause blood vessels to open up?

A. Taking exercise.

B. Listening to unpleasant music.

C. Bursting into laughter.

D. Taking drugs like statins.

3. It can be inferred from the passage that _____.

A. blood clots are caused by heart attacks and strokes

B. music is better than chocolate for your health

C. the style of music has different effects on different people

D. a person's overall health is more influenced by how much exercise he gets

4. What's the best title of the passage?

A. Pleasant Music Cures

B. Research into Blood Vessel

C. Music and Heart Attack

D. Music and Happiness

某一地区发生小儿麻痹症疫情，现场调查12～23月龄儿童的小麻糖丸覆盖率，结果如下：人群中儿童全程免疫覆盖率为60％，人群中儿童非免疫接种的比例为20％，病例中儿童全程免疫覆盖率为10％，病例中非免疫接种的比例为70％，则疫苗保护率为（）

A.43％

B.60％

C.5％

D.86％

E.95％

乙型强心苷苷元甾体母核中C-17位上的取代基是

A．醛基
B．六元不饱和内酯环
C．糖链
D．羧基
E．五元不饱和内酯环

用鼠标右击一个控件时出现的菜单一般称为（）。