为了测定能使带火星的木条复燃时氧气的最低含量是多少，课外活动_爱下问搜题

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问题选择题

为了测定能使带火星的木条复燃时氧气的最低含量是多少，课外活动小组的同学们进行了实验探究。他们设计的实验方案是先将氧气和空气按不同的体积比收集在集气瓶里。收集气体的装置如图。收集气体的方法是：在100 mL集气瓶里装满水，塞紧胶塞并关闭活塞b，打开活塞a通入氧气，把瓶里的水排入量筒，当量筒内的水达到设定的体积后立即关闭活塞a，然后打开活塞b通入空气，把瓶里的水全部排入量筒。若要收集一瓶含氧气的体积分数约为60%的气体，则停止通入氧气时量筒内水的体积约为（提示：空气中也有氧气）

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A．75 mL

B．60 mL

C．40 mL

D．25 mL

答案

答案：A

填空题

请你给下面四幅图排列正确的顺序，再根据课文内容填空。

(1)青蛙成长的顺序应为__________________________________。

(2)小蝌蚪，大大的________，________的身子，甩着长长的_______。过了几天，长出了两条________，再过了几天，长出了两条_________，又过了几天， _______变短了，不知什么时候，小青蛙的_______不见了。

完形填空

Thanks to a combination of young businessmen, large numbers of university students and revitalization (新生) efforts by the local and national governments, today’s Nanjing has an      36   of youthful exuberance (繁茂) that would have been    37   only a few decades ago.   38  , the city, a booming city of 6.5 million on the banks of the Yangtze River some 185 miles west of Shanghai, bears    39   resemblance to the former capital of China that suffered the worst cruelty and violence of World War II.
40   Nanjing has shown a remarkable capacity for reinvention during its 2,500-year history. And in recent years, the city has moved    41   its tragic past to become a vital engine of China’s economic growth, thanks    42   to its position in the middle of China’s prosperous eastern seaboard. Growth has also    43   thanks to improved ground transportation: A new bullet train linking Nanjing and Shanghai started service last year,    44   travel time between the cities from several hours to just 75 minutes, and a Beijing-Shanghai high-speed line is    45  to open later this year, with a stop in Nanjing. Within the city, two metro lines were built in the last few years; 15 more are planned to begin service by 2030.
Signs of Nanjing’s    46   wealth and optimism can be seen everywhere. In the heart of the downtown Xinjiekou district, a bronze statue of Sun Yat-sen,    47   the father of modern China, looks    48   over a busy    49   area.
There is perhaps no more    50   symbol of the city’s transformation than the Zifeng Tower, a 1,480-foot skyscraper that opened its doors last May.    51   offices, restaurants and an InterContinental hotel, the tower is the second-tallest building in China and billed as the seventh-tallest in the world.
Underlying all this development is a large Chinese and    52  student population — there are several major universities, plus a branch of Johns Hopkins’s international studies school. In fact, art and music    53   in all sorts of places.
On a larger    54  , local government officials and private investors are pushing the city as a rising center for contemporary art and architecture, hoping to attract    55   from the neon-bathed streets of its neighbor Shanghai.

A．unforgettable

B．unthinkable

D．unnecessary

B．Regretfully

D．Consequently

A．in addition

D．accelerated

B．well-received

C．traditional

A．businessmen