与二氢黄酮反应后产生天蓝色荧光的是A．HC1-Mg反应B．NaBH4反应C．MgAc

8000万是一个______位数，8表示______．

It’s interesting that the arrival of snow has effect on people in different countries. For some countries it is an important happening to celebrate each year, while for others a catastrophe(灾害) or even a wonder.

　　But there are countries between these two kinds that normally expect snow some time over the winter months, but never receive snow regularly or in the same quantities every year. Britain is one of them, for which the arrival of snow quite simply causes problems. Within hours of the first snowfalls, however light, roads are blocked, trains and buses have to stop in the middle of the way. Normal communication is affected as well: telephone calls become difficult and the post immediately takes more time than usual. And almost within hours, there are also certain shortages----bread, vegetables and other things-----not because all these things can no longer be produced or sent to shops, but mainly because people are frightened and go out and store up with food and so on…just for fear that something bad should happen.

　　But why does snow have this effect? After all, the Swiss, the Austrians and the Canadians don‘t have such problems. It is simple because there is not enough planning and preparation. We need money to buy equipment to deal with snow and ice. To keep the roads clear, for example, requires snow-ploughs(扫雪机) and machines to spread salt. The reason why a country like Britain does not buy snow-ploughs is that they are used for a few days in any one year, and the money could be more useful in other things such as hospital, education, helping the old and so on..

　小题1:According to the writer, Britain is a country ________.

A．which has regular snow

B．which is not well prepared for snow

C．for which snow is a catastrophe

D．for which snow is a wonder　　小题2:After a few hours’ snowing there are often some shortages of food because ______.

　　A. shops have closed down B. people buy as much as they can

　　B. farmers cannot produce any more D. people eat more vegetables in winter

　　小题3:The words "two kinds" in the passage mean the countries ______.

A．which have weather as yearly happening to celebrate or as rare(少见) weather

B．which either have heavy snow or light snow

C．to which snow either causes problems or no problems

D．which either have snow-ploughs or no snow-ploughs

在短期总供给曲线时，总需求的变动会引国民收入与价格水平反方向变动。

持续性钝痛或隐痛多表示_______或_______病变。阵发性腹痛多表示_______脏器发生梗阻或痉挛性病变。持续性腹痛伴阵发性加重多表示和_______并存。

班主任工作计划一般包括( )

A．学期工作计划和具体活动计划
B．全面计划和专题计划
C．课内计划和课外计划
D．教学工作计划和思想工作计划