促进儿茶酚胺类物质释放的药物是（）。 A．氨茶碱  B．沙丁胺醇  C．异丙托溴铵

阅读理解。

                                                     Stingrays (黄貂鱼)

    Stingrays are pancake-shaped fish, and you'd never guess it: they're close cousins of sharks.The

smallest kinds are about the size of a dinner plate. But some 4-metre stingrays live in the waters near

Australia. About 170 different kinds of stingrays live in the oceans around the world. And some live

in freshwater too. In South America, a few kinds swim in the Amazon and other rivers that flow into

the Atlantic. One ocean kind, the Atlantic stingray, also

lives in the St. Johns River in Florida.                        

      A stingray has a mouth and nostrils(鼻孔) on the bottom of its body. These nostrils are for smelling,

not for breathing. When water flows into a stingray's nostrils, the fish may pick up the smells of creatures

it wants to eat. It can also find prey (牺牲者) by sensing the tiny amount of electricity that animals give

off. Slowly, slowly the fish hunts by moving along the ocean or river bottom. When it senses a worm,

clam, shrimp, or other creature, it flaps (拍打) its fins until the prey is uncovered. Then the fish lies down

over the prey, sucks it in, and crunches it with its small teeth. A stingray's flat shape helps it hide. It stirs

up a cloud of sand by flapping its big, flat fins. When the sand settles down over the fish, everything is

covered but its eyes, breathing holes, and sometimes its tail. Its tail gave the "sting" to a stingray's name.

When a stingray is attacked by an enemy, it whips its tail around. Then a sharp stinger releases a powerful poison into the enemy. When stingrays are on the ocean bottom, it's easy for a diver to step on one by

mistake. Then the fish usually stings the person in the ankle. The poison is very painful, and the wound

may hurt for a day or two. Worse yet, pieces of the stinger can break off and infect the ankle. But

stingrays don't chase after prey or people to sting them. In fact, divers can swim among friendly stingrays

without getting hurt.

1. Why did the author write the article "Stingrays"?

A. To tell readers an exciting story about the ocean.

B. To give readers facts about an interesting fish.

C. To warn readers about dangers in the ocean.

D. To teach readers how fish hunt their prey

2. It is easy for a diver to step on a stingray by mistake because stingrays ______.

A. are of many different sizes                

B. can cover themselves with sand

C. move slowly above the ocean floor        

D. live in freshwater as well as in oceans

3. Why does a stingray flap its fins when it feels prey?   

A. To smell the prey.

B. To escape from the prey.  

C. To find the prey.  

D. To frighten the prey.

4. How might a sting from a stingray become infected?   

A. Poison from the stinger gets into the wound.

B. Pieces of the stinger come loose in the wound.

C. Electricity from the stinger shocks the wound.

D. Fins beside the stinger throw sand into the wound.

“江苏省”这个名词从地理区域的划分的角度，属于（　　）

A．自然区域

B．经济区域

C．行政区域

D．省级区域

眼睑软组织挫裂伤、皮下淤血时，治疗方法不正确的是（）

A.清创缝合并加压包扎

B.24小时内热敷

C.口服止血药

D.14小时内冷敷

E.合理应用抗生素预防感染

股利收益率是指投资者当年获得的所有的股息与股票市场价格之间的比率。

减速机是将电动机（）的转速变成轧辊所需的转速。