请写出三个图形，它们既是轴对称图形，又是中心对称图形，它们是（ ）。

随着市场经济体制的日臻完善，利用先进技术提高产品的科技含量以增强市场竞争力．已成为各企业集团的共识。______。
填入划横线部分最恰当的一句是：

A．这些产品不仅促使了消费结构的改变．同时也促进了科学技术的开发和应用
B．高技术产品日益增多，这些产品不仅促使了消费结构的改变，同时也促进了科学技术的开发和应用
C．这些产品不仅促进了科学技术的开发和应用．同时也促使了消费结构的改变
D．高技术产品日益增多。一方面这些产品促使了消费结构的改变．另一方面促进了科学技术的开发和应用

若x=-2是一元二次方程x²=c²的一个根，则常数c是（　　）

A．±2

B．2

C．-2

D．4

As dangerous as sharks may have seed to people after watching Jaws, which was released on June 20,1975, the recent disastrous decrease in their numbers show that people have proven far more dangerous to sharks.

This disastrous decline is due in large part to commercial fishing of sharks. “The market for

shark fins（鱼翅）in East Asia opened up thanks to changes in their economy, increasing their

ability to spend money on things such as shark fin soup,” Burgess said.

However, the biggest worry for sharks and their relatives, the skates and rays, which are suffering a similar fate, “is how they are killed incidentally when fishermen try and take other fish—the problem of bycatch（渔业混获）,” Burgess explained. “They may be thrown back afterward, but they’re still dead.”

The key of the problems behind bringing sharks back is that “they’re not the same as other fish,” Burgess said, “Sharks are slow growing and slow to reach maturity. Sharks are live bearers, which means females keep their young in their body just like us, but instead of nine months, it takes 12 to 18 months or more in sharks. Also, sharks generally can’t give birth again until a year after they’ve given birth—sometimes they’re on a three-year cycle. So once you get a shark population knocked down, this ‘life in the slow lane’ means that recovery is measured in decades rather than years.”\

Burgess said, “I’m on the recovery team for it, but the recovery plan for that is over the course of 100 years. So I won’t see them recover, nor will you, nor will your children. That’s what it means when these animals go down—they’re down a long time.”

Any measures aimed at saving sharks must not only consider byeatch, “which is the real killer right now,” but also encourage interactional cooperation, Burgess said.

“Sharks are very migratory, and many species cross borders,” he said. “We can protect them only by getting many govemment to come aboard. That’s the hardest part about this.”

小题1:The text mainly tells us      .

A．shark fins are valuable

B．sharks are dangerous

C．bycatch brings bad effects

D．sharks are in danger小题2:The number of sharks is decreasing mostly because of     .

A．the film Jaws

B．commercial interests

C．changes in economy

D．shark fin soup小题3:Bringing sharks back is difficult because     .

A．they’re like the other fish

B．their reproductive rate is slow

C．they can’t give birth again

D．their life cycle is only 3 years小题4:What can be concluded from the last paragraph?

A．Sharks live the way human beings do.

B．It’s time many govemments cooperate.

C．Sharks’ migration takes a very long time.

D．Bycatch shouldn’t be forbidden by intemational laws.小题5:The test is most probably a        .

A．newspaper ad

B．book review

C．science news report

D．science fiction story

食积气滞应首选的药物是（）

A.山楂

B.稻芽

C.鸡内金

D.莱菔子

E.浮小麦

无黏性土的密实状态对其工程性质影响不大。