对建筑物有潜在威胁的下列()项地段,不应选作建筑场地。() A.泥石流 B.岩溶微发

题型:多项选择题

问题:

对建筑物有潜在威胁的下列()项地段,不应选作建筑场地。()

A.泥石流

B.岩溶微发育

C.崩塌

D.土洞强发育

考点:岩土工程专业知识第二章浅基础第二章浅基础题库
题型:多项选择题

Malthusian fears that population growth will outstrip food supplies have been widely discounted as food production has kept well ahead of growing human numbers in the last half century. While population doubled, food supply tripled, and life expectancy increased from 46 in the 1950s to around 65 today. But more recently, some experts have once again been sounding the alarm about a possible food crisis.

The reason lies in the combined impact of many factors including climate change, forest denudation, land degradation, water shortage, declining oil supplies, species extinction, destruction of coastal ecosystems and the growing demands for a meat-rich diet from newly developed parts of the world.

At the root of all these problems has been the ruthless exploitation of the earth’s resources, fuelled by growing affluence in some parts of the world and desperate poverty in others. Between 1980 and 2000, global population rose from 4.4 billion to 6.1 billion, while food production increased 50 per cent. By 2050, the population is expected to reach 9 billion.

Data shows that while grain yields per acre have been increasing, the rate of increase has been slowing since the days of the Green Revolution in the 1970s. Most of the benefits of irrigation, machinery, fertilizer and plant breeding have already been realized. The production of grain per acre is close to the maximum obtainable through photosynthesis.

To keep up with the growth in human population, more food will have to be produced over the next 50 years than has been during the past 10,000 years combined, said the participants of the recent UN-backed forum in Iceland on sustainable development. It is, of course, possible that new technologies, smart environmental management and sensitive social policies will combine to good effect to usher in a new green revolution. But as grain reserves have fallen to their lowest level for many years, this cannot be guaranteed.

At the 1996 World Food Summit political leaders from 186 countries pledged to halve the number of hungry people in the world by the year 2015, or a reduction of 20 million each year. At that time, about 800 million people were reported to suffer from under- nourishment. In 2007 estimates from the UN Food and Agriculture Organization (FAO) suggest that there are 854 million people who do not get enough to eat every day. "Far from decreasing, the number of hungry people in the world is currently increasing," said FAO Director-General Jacques Diouf. (Of course, world population has increased by some 800 million in that time, so food supplies have kept up relatively well, but have failed to reach an increasing number, let alone reduce the total going hungry.)

According to the last paragraph, what happened in the year of 2007()

A. There was an annual reduction of 20 million poor people

B. The number of starving people increased by 50% against 1996

C. The number of people suffering from malnutrition kept up well

D. Food supplies went up due to the application of new technologies

题型:多项选择题

交分道岔由菱形交叉、双转辙器及连接曲线等部分。

题型:多项选择题

有些地理学家认为如果世界上未勘探过的地区的石油与已勘探过地区的石油一样普遍,那么我们现在对地下石油贮备的估算,必须要乘以万倍了。由此我们可以得出结论:即使假定未来的石油消费加速增长,我们至少可以再满足5个世纪整个世界的石油需求。 为了得出上述结论,作者必须假设下面哪个( )

A.人们有可能在未开发地区再发现石油。

B.石油的消费速度不会迅速增长。

C.在至少500年内,石油仍将是重要的能量来源。

D.世界人口将实现并保持零增长。

题型:多项选择题

按照其工作原理分类,下列类型甲烷传感器属此类的是()

A、电容式

B、催化燃烧式

C、压电式

D、磁阻式

题型:多项选择题

后危机背景下国际贸易发展的特征?

更多题库