求如图所示的交变电流的有效值，其中每个周期的后半周期的图象为半个周期的正弦曲线（

设集合M={x|f（x）=0}，N={x|g（x）=0}，则方程f（x）•g（x）=0的解集是（　　）

A．M∩N

B．M∪N

C．M、N中的某一个

D．不确定

Of the thousands of different kinds of animals that exist in the world man has learned to make friends with an enormous number. Some are pets, and offer him companionship, some give protection, and some do hard work which man can not do for himself. Dogs , which serve man in all three capacities(能力), are found in various species in all countries of the world. The    Husky can live in the cold polar regions,and the Saluki is at home in the hottest parts of Central Africa.The inhabitants (居民)of certain countries are dependent for their very lives on the camel. In the West Indies the little donkey, strong and sure-footed, carrying heavy loads even in mountainous, places, is a familiar sight.

Trained and tamed for many generations, domestic animals are not accustomed to roaming in search of food and shelter. They look to their masters to provide for their needs, and as  long as these are supplied, they are content to do what their masters require.

All domestic animals need proper food .It must be suitable for them, sufficient in quantity, fresh and clean. Some people feed a pet dog or cat on odds and ends of table scraps(剩饭), and then wonder why the animal seems tired and dull. The quantity of food depends on the size of the animal and the amount of exercise it takes. Overfeeding is as bad as underfeeding. Containers for food and water must be washed regularly if the animal is to maintain good health.

Even well-cared-for animals may sometimes fall ill. If this happens, the wise master seeks the best advice he can get. All sorts of medicines and treatments are available for sick animals, and in some countries organizations exist to provide them free of at a cheap price. Useful, friendly, hardworking animals deserve to have some time, money and attention spent on their health.

小题1:What main idea does the author want to convey in the first paragraph?

A．There exists thousands of species of animals in the world.

B．Man came to establish a close relationship with a number of animals.

C．In some regions a donkey seems to be a very useful beast.

D．An animal will be useless unless domesticated.小题2:When an animal doesn’t get enough food, it will probably    

A．refuse to obey its master

B．immediately fall ill

C．require its master to offer some food

D．seek for food on its own小题3:Which of the following is NOT true of dogs according to the passage?

A．They can act as friends, guards ,and servants to man.

B．They have great adaptation for the environment.

C．There live a great variety of species of dogs on the globe.

D．The Husky and the Saluki are the strongest species ever known in the world小题4:To keep a domestic animal physically fit, its owner is advised    

A．not to hesitate to spend enormous amount of money on it

B．to pay attention to its proper feeding

C．not to allow it to take excessive amounts of exercise

D．to join some sort of pet-keeping organizations小题5:Which of the following would be the best title for this passage?

A．Domesticated Animals-Man’s Best Friends

B．Proper Diet- the Road to Health

C．The Advantages of Raising Domestic Animals

D．Some Tips on Pet- keeping

CMC的那种工作模式，只能在地面使用？（）

A.NORMAL MODE

B.INTERACTIVE MODE

C.STANDBY MODE

D.HOT-STANDBY MODE

下列哪项提示有脑干损伤

A．中间清醒期
B．Battle征
C．脑脊液耳漏
D．去大脑强直
E．头痛、呕吐、视神经盘水肿

《西方文明史》谈到：“这种氛围不可避免地产生了十八世纪占支配地位的观念：科学方法是研究社会活动和自然现象的惟一可行的方法。由于具有自然属性的世界正被人所认识，因此启蒙思想家认为具有社会属性的世界也可以用科学的方法去认识，这已成为一种共识。”对此解释最准确的是（）

A.肯定了十八世纪科学的进步

B.反映了十八世纪启蒙运动的产生

C.社会活动和自然现象都是可认识的

D.启蒙思想家崇尚科学和理性