问题 填空题

将滤纸条浸5%硝酸银溶液,放于乙炔取样口下,吹气约半分钟,试纸显黄色,是乙炔气体含有();试纸显黑色是含有()。

答案

参考答案:PH3;H2S

单项选择题
阅读理解

阅读理解

阅读下列短文, 根据短文内容, 从短文后的选项中选出能填入空白处的最佳选项

      __1__  To begin with, cleaner environment, enjoying the game with hundreds of sports athletes and

entertainment stars, and the opportunity of contacting people from all over the world seem exciting to the

citizens.  2__  In most cases, bidding for the Olympics is well supported by both the public and the

central government.

      Unfortunately, this is not the entire view of the pretty picture. If looking from another angle, the

Olympic bid might bring about some sideeffects to a city.

     __3__  It includes the increasing pollution of cars, more pressure on water resources, huge amount

of wasted leaflets and other materials used for public activities, which are most probably neglected. In

order to broaden the streets, some trees may have to be cut. Reduction of farmland may be caused b

y the need of setting up new sports centers or accommodation facilities. These environmental

consequences can be especially serious in a resourcelimited and crowded city in a thirdworld country.

     Besides, if not well managed and organized, the big event may not be so beneficial, and the new

facilities may be forever empty after the games.__4__

     Finally, let's think about the lowincome groups in the city.__5__ More tax, more fees, more

expensive property prices, and higher cost of living. These definitely are not good news for them.

A. Hosting the Olympics surely would bring about much gain to a city.

B. We can only benefit from it for a short time.

C. What will they get from the Olympics bidding?

D. First of all, it will bring a lot of environmental problems.

E. There are many reasons for not hosting the Olympic Games.

F. There have been cases that host cities ended up with large debts.