进口属于列入《中国禁止进口、限制进口技术目录》的技术，须经商务部各主管部门审批同意后

读我国四大地理区域示意图，完成下列问题。

（1）下列关于我国四大地理区域的叙述，正确的是（   ）

A．甲区域地势低平，河湖密布，淡水渔业发达

B．乙区域的地形以平原和高原为主，耕地以旱地为主

C．丁区域距海遥远，气候干旱，种植业以灌溉农业为主

D．丙区域海拔高，三江源地区是长江、黄河和珠江三大河流的发源地（2）填表比较丁、丙两大区域的差异：

当一个主轴的支承是由几个轴承组合而成时，主轴的轴向窜动是由所有轴承共同作用的结果。

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.

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

C．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

泵轴承过热的原因不可能是（）。

A、轴承过紧

B、预载过大

C、不适当冷却

D、润滑油过少

磁感应开关目前已在矿井提升机上得到广泛应用，主要用于过卷开关、提升容器与（）的齐平信号、等实际位置信号的发送。