采用模仿创新战略必须具备的前提有()。A.起步较早 B.引进者拥有技术引进的能力 C

某地区有土地520平方千米，其中沙漠荒地20平方千米，由于该地区的乱砍滥伐，该地区以每年4平方千米的速度沙漠化，如不加治理，8年后该地区沙漠化地带占整个地区的百分数是______．

Every minute must _______ full use of _____ our lessons.

A．be made; doing

B．make ; do

C．make; done

D．be made ; todo

Scientists are placing robotic dogs in the homes of lonely old people to test whether they can improve the quality of life for humans. Alan Beck, an expert(专家) in human-animal relationship, and Nancy Edwards, a professor of nursing, are leading the animal-assisted study on the effect of robotic dogs on old people’s depression (沮丧) , physical activity, and life satisfaction.

In the study, the robot, called AIBO, is placed for six weeks in the houses of some old people who live alone. Before placing AIBO in the home, scientists will collect baseline data(数据) for six weeks. These old people will keep a diary to note their feelings and activity before and after AIBO. Then, the scientists will review the data to test if it has produced any changes in the life of its owner.

“I talk to him all the time, and he responds to my voice,” says a seventy-year-old lady. “When I’m watching TV, he’ll stay in my arms until he wants down. He has his own mind.”

The AIBOs respond to certain orders. The scientists say they have some advantages over live dogs, especially for old people. Often the elderly are disabled and cannot care for an animal by walking it or playing with it. A robotic dog removes exercise and feeding concerns.

“At the beginning, it was believed that no one would relate(与……相关) to the robotic dog, because it was metal and not furry.” Beck says. “Hopefully, down the road, these robotic pets could become a more-valuable health helper. They will record their masters’ blood pressure, oxygen levels or heart rhythms(心律). AIBOs may even one day have games that can help stimulate(刺激) older people’s minds.”

小题1:The purpose of Beck and Edwards’ study is to _____________.

A．understand human-animal relationship

B．make lonely old people’s life better

C．find the causes of old people’s loneliness

D．improve the animal-assisted research小题2: In the research, the old people are asked to _____________.

A．note the activities of AIBOs

B．keep AIBOs at home for 12 weeks

C．record their feelings and activity

D．study the collected information小题3:What does the underlined word “removes” mean?

A．moves again

B．is movable

C．doesn’t need

D．need小题4:What is the better point of AIBO than live dogs?

A．It is easier to keep at home.

B．It can help the disabled people.

C．It responds to all the human orders.

D．It can watch TV with its owner.小题5:The writer seems to suggest that the future robotic dogs may__________.

A．cure certain diseases

B．keep old people active

C．change people’s ideas

D．look more like real dogs

无菌切口消毒顺序是

A．以切口为中心，自上而下
B．以切口为中心，自下而上
C．以切口为中心，向四周
D．由四周向切口
E．无一定的顺序

永久性结构的微管有鞭毛、纤毛等，临时性结构为纺锤体等。