lifetimes of reserves are about the same today as they were 30–40 years ago. long-term inflation-adjusted prices have gone down in most cases. lower-grade ores are now affordable to mine because of “improved technologies, economies of scale and increased efficiency.”[107] * Mineral “...
【答案】The population of the small island was 500 thirty years ago.【解析】题干给出的汉语意思是“三百年前,这个小岛的人口大概是五百”,给出的英文提示是“The population of...is... ”,意思是“...的人口是”,此处The的首字母大写,说明这个短语应放在句首,主语是The population of ...,谓语动词...
There are more than 7 billion people in the world today, and the population is still growing. Two thousand years ago, there were only around 250million people in the world. Over the next 1,700 years, the number doubled to 500 million. In the next 200 years, the world population grew ...
1 ___ years ago,the population of the world was over 500 million.( )A.Four hundredsB.Four hundredC.Four hundred ofD.Four hundreds of 2B )2years ago, the population of the world was over 500 million.A. Four hundredsB. Four hundredC. Four hundred ofD. Four hundreds of 3【题目】(...
A systematic population survey and migration tracking of black-necked cranes in Qinghai revealed that the population of these cranes there has exceeded 2,600 -- an increase of more than 1,400 compared with the population 10 years ago.
indicating no current gene flow between the population groups. The curves reached a value of 0.5 at ~40 kya and 100 kya ago for the two comparisons, respectively (Fig.2b), and converged to their maximum values at about 100 kya and 500 kya, respectively. A previous study suggested...
The population (人口) problem may be the (41) one of the world today. The world’s (42) is growing fast. Two thousand years ago, there were only 250 million people (43) the earth. Four hundred years ago, the number was (44) 500 million. But at the beginning of (45) century, ...
“Our counselor did an informal survey a couple years ago and found that we had only one family that made its sole living off of farming,” Rush said. “We had a lot that farmed on the side, but only one that farmed full-time. That’s a huge shift for this community.” ...
The current populations of the Crested Ibis including wild, captive and reintroduced populations were derived from seven individuals approximately 40 years ago, so each of them is an inbred population (Li et al.2014; Feng et al.2019; Fu et al.2019). However, the Crested Ibis has survived ...
The population problem may be the___one of the world today.The world's population is growing___.Two thousand years ago,there were only 250 million people___the earth.Four hundred years ago,the number was___500 million.But at the beginning of the___century, the world’s population was...