问题 问答题 简答题

简述肠型猪瘟的剖检变化特点。

答案

参考答案:

肠型猪瘟病程长。病尸消瘦可视粘膜苍白。剖检除见不同程度的单纯型猪瘟病变外,在肠管由于并发沙门杆菌的混合感染,故在盲肠、结肠及回盲瓣处,形成灶状的纤维灶坏死性肠炎,形成“扣状肿”或扣状坏死。

完形填空
In the past, man did not have to think about the protection of his environment. There were few people on the earth, and natural   36  seemed to be unlimited.
Today things are   37  . The world has become too   38  . We are   39  our natural resources too quickly, and at the same time we are   40  our environment with dangerous chemicals. If we   41  to do this, human life on earth will not   42 .
People realize today that if too many   43  are taken from the sea, there will soon be none left. Yet, with modern fishing   44  , more and more fish are caught.
We know that if too many trees are cut down,   45  will disappear and nothing will  46  on the land. Yet, we continue to use bigger and more powerful machines to   47  more and more trees.
We realize that if rivers are polluted with waste products from factories, we will die.   48  , in most countries waste products are still put into rivers or into the sea, and there are few laws to   49  this.
We also know that if the   50  of the world continues to rise at the present rate, in a few years, there won't be enough food. What can we do to solve the   51  ? If we eat more vegetables and less   52  , there will be more food available for everyone. Land that is used to grow crops feeds five times more people than land where animals are kept.
Our natural resources will   53   longer if we learn to recycle them. The world population will not   54  so quickly if people use modern methods of birth control.
Finally, if we   55  people to think about the problems we shall have a better and cleaner planet in the future.
小题1:
A.resourcesB.sourcesC.materialsD.matter
小题2:
A.commonB.the sameC.changeableD.different
小题3:
A.crowdedB.pollutedC.dirtyD.busy
小题4:
A.producingB.using upC.reducingD.making
小题5:
A.protectingB.savingC.pollutingD.fighting
小题6:
A.tryB.continueC.stopD.have
小题7:
A.liveB.lastC.continueD.survive
小题8:
A.fishB.seagullsC.crocodilesD.frogs
小题9:
A.polesB.boatsC.methodsD.ideas
小题10:
A.mountainsB.the seaC.cropsD.forests
小题11:
A.growB.plantC.saveD.cut down
小题12:
A.plantB.cut downC.saveD.burn down
小题13:
A.ThusB.HoweverC.Generally speakingD.Therefore
小题14:
A.encourageB.neglectC.stopD.wake up
小题15:
A.productionB.pollutionC.populationD.revolution
小题16:
A.pollutionB.environmentC.questionsD.problems
小题17:
A.fruitB.meatC.fishD.grain
小题18:
A.useB.stayC.keepD.last
小题19:
A.raiseB.riseC.runD.grow
小题20:
A.forceB.helpC.educateD.show
单项选择题