强势带弱势原则，是根据()来决定的。A、施教者的能力  B、婴儿的能力  C、婴儿个

已知圆锥的侧面积为12π.

（1）求圆锥的母线l关于底面半径r的函数关系式，并求出r的取值范围；

（2）当圆锥的全面积为16π时， 求圆锥的侧面展开图的圆心角度数.

阅读理解

     Fish have ears. Really. They're quite small and have no opening to the outside world carrying sound

through the body. For the past seven years, Simon Thorrold, a university professor, has been examining

fish ears, small round ear bones called otoliths.

   As fish grow, so do their otoliths. Each day, their otoliths gain a ring of calcium carbonate (碳酸钙).

By looking through a microscope (显微镜) and counting (数) these rings, Thorrold can determine the

exact age of a young fish. As a fish gets older, its otoliths no longer get daily rings. Instead, they get yearly

rings, which can also be counted, giving information about the fish's age, just like the growth rings of a

tree.

Ring counting is nothing new to fish scientists. But Thorrold has turned to a new direction. They're

examining the chemical elements (元素) of each otolith ring.

     The daily ring gives us the time, but chemistry tells us about the environment in which the fish swam on

any given day. These elements tell us about the chemistry of the water that the fish was in. It also says

something about water temperature, which determines how much of these elements will gather within

each otolith ring.

   Thorrold can tell, for example, if a fish spent time in the open ocean before entering the less salty water

of coastal areas. He can basically tell where fish are spending their time at any given stage of history.

   In the case of the Atlantic croaker, a popular saltwater food fish, Thorrold and his assistant have

successfully followed the travelling of young fish from mid-ocean to the coast, a journey of many

hundreds of miles.

   This is important to managers in the fish industry, who know nearly nothing about the whereabouts (行踪) of the young fish for most food fish in the ocean. Eager to learn about his technology, fish scientists

are now lending Thorrold their ears.

1. What can we learn about fish ears from the text? 

A. They are small soft rings.            

B. They are not seen from the outside. 

C. They are openings only on food fish.  

D. They are not used to receive sound.

2. Why does the writer compare the fish to trees? 

A. Trees gain a growth ring each day. 

B. Trees also have otoliths. 

C. Their growth rings are very small. 

D. They both have growth rings.

3. Why is it important to study the chemistry of otolith rings? 

A. The elements of the otoliths can tell the history of the sea. 

B. Chemical contents (含量) of otoliths can tell how fast fish can swim. 

C. We can know more about fish and their living environment. 

D. Scientists can know exactly how old a fish is.

4. How would you understand "fish scientists are now lending their ears"?

A. They are very interested in Thorrold's research findings.

B. They want to know where they can find fish.

C. They lend their fish for chemical studies.

D. They wonder if Thorrold can find growth rings from their ears.

为了维持家庭的生存、生产、教育和生活保障，家庭要在吃、穿、住、用等方面进行必要的支出，这是家庭的（）功能

A．生产功能

B．人力资本的投资功能

C．消费功能

D．生活福利和保障功能

西方政治学和马克思主义政治学关于政治概念的区别主要是（）

A.西方政治学的政治概念重点围绕政治现象本身展开论述

B.马克思主义政治学的政治概念深刻地揭示了政治的本质

C.西方政治学的政治概念重点围绕政治的本质展开论述

D.西方政治学的政治概念强调政治活动总是与人们的意志和利益相联系

E.马克思主义政治学的政治概念真心实意地表达了为人民谋取利益的主张，并指出了促成人民利益真正实现的具体途径。

渠道的输水损失包括以下四个部分：（）

A、干渠、支渠、斗渠及农渠等四级渠道的水量损失。

B、渠床土质、地下水埋深、渠道的工作制度及输水时间。

C、自由渗流、顶托渗流、渠床土质、与渠道的工作制度等。

D、渠道水面蒸发损失、渠床渗漏损失、闸门漏水与渠道退水等。