当用户程序执行访管指令时,中断装置将使CPU( )。A.维持在用户态 B.维持在内

题型:多项选择题

问题:

当用户程序执行访管指令时,中断装置将使CPU( )。

A.维持在用户态

B.维持在内核态

C.从内核态转换到用户态

D.从用户态转换到内核态

考点:普通考研计算机学科专业基础综合考研操作系统
题型:多项选择题

用NA表示阿伏加德罗常数的值,下列叙述正确的是 [ ]

A. 11.2L氯气含有的分子数为0.5NA

B. 32g氧气中所含有的氧原子数为2NA

C. 2.4g镁变成镁离子,转移的电子数为0.1NA

D. 1L 0.3mol/L K2SO4溶液中含有钾离子数为0.3NA

题型:多项选择题

Britain’s seed(种子) bank, the only one in the world aiming to collect all of the planet’s wild plant species, has reached its goal of banking 10 percent by 2010.

The Millennium Seed Bank Project, run by Kew Gardens—one of the oldest botanical(植物的)  gardens—will officially place the 24,200th species on Thursday, a pink, wild banana from China.

More than 50 countries are now on board with Kew's giant task but vast places of the globe, including India and Brazil, still need to join in and donate seeds, director Paul Smith said.                                                                                                                                                            

The seed bank is one of the largest and most diverse(多样的) in the world with more than 1.5 billion seeds. Its goal is to help protect the planet’s bio-diversity during a time of climate change.

The wild banana seed is under threat of extinction(灭绝) in southwest China from agricultural development. It is a vital food source for Asian elephants and important for growing bananas for human eating.

Stored at minus-20 degrees centigrade, so they can last for thousands of years, the seeds await the day that scientists hope never comes—when the species no longer exist in the wild.

It is a race against time, Smith said, because in the last ten years alone, 20 plants held in the bank have already been wiped out in the wild. He estimates that between a third and a quarter will become extinct this century.

"It is pressing and it is happening now. An area, the size of England, is cleared of primary vegetation(植被)every year." Smith said.

Because most of the world's food and medicines come from nature, protecting wild plant species is quite important, scientists say. There are already many other seed banks safeguarding food crops, which only account for 0.6 percent of plant diversity.

For Kew's next goal—to collect a quarter of wild varieties(种类)by 2020—the botanists need 10 million pounds a year, or a further 100 million pounds on top of the 40 million they have already been granted.

小题1:What’s the final purpose of the Britain’s seed bank?

A.To collect enough money for the project.

B.To safeguard food crops.

C.To protect wild plants from extinction.

D.To help scientists study wild plants.小题2:We can learn from the passage that _______.

A.the seeds in the bank can be used now and then all over the world

B.India and Brazil haven’t joined in the Seed Bank Project at present

C.there is only one seed bank in the world at present

D.the wild plants in places like India and China will never die out小题3:What does the underlined word “it” in paragraph 7 refer to?

A.The extinction of plant species.

B.The Millennium Seed Bank Project.

C.Britain’s seed bank.

D.Kew Gardens’ next goal.小题4:Which of the following isn’t spoken about in the passage?

A.The global partnership of collecting wild plant species.

B.The temperature condition of the wild plant species in the bank.

C.The government’s support for the seed bank project by giving money.

D.Scientists’ concern on the extinct wild plant species.

题型:多项选择题

画面多用山水、人物故事、花鸟鱼虫等的彩画是(  )

A.苏式彩画

B.旋子彩画

C.和玺彩画

D.包袱彩画

题型:多项选择题

横向稳定杆是为了提高悬架的什么的刚度?

题型:多项选择题

军种是按主要作战领域、任务和(),对军队的构成成分划分的基本种类。通常分为陆军、海军、空军。

A、兵种

B、专业

C、性质

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