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1、精品好文档，推荐学习交流1.（10分）如图所示：已知节点1－2间的阻抗为ZL=，母线2送出负荷为10+j8MVA，母线2电压为110kV，试计算母线1处的电压和功率。解：等值参数计算：每个参数1分，等值电路1分作等值电路如右图所示。末端负荷功率：阻抗中功率损耗：首端功率：首端电压计算3分阻抗中电压降落：首端电压：仅供学习与交流，如有侵权请联系网站删除谢谢3精品好文档，推荐学习交流kV首端功率计算3分杨浦区2019学年第一学期高三模拟质量调研英语学科试卷2019.12Ⅱ.GrammarandVocabular
2、ySectionADirections:Afterreadingthepassagebelow,fillintheblankstomakethepassagecoherentandgrammaticallycorrect.Fortheblankswithagivenword,fillineachblankwiththeproperformofthegivenword;fortheotherblanks,useonewordthatbestfitseachblank.KillerRabbitsYou’dnev
3、erthinkofrabbitsasdreadful,destructivecreatures,wouldyou?Rabbitsarecuteandlove-able.However,Australiansdiscovered(21)________harmthesecutecreaturescandothehardway.RabbitswereintroducedtoAustraliain1788asfoodanimals.By1827,theywererunningaroundlargeestates,
4、andin1859,disasterstruck.Amanreleased12wildrabbitsontohispropertyforhuntingandhe(22)________havethoughtthatwasharmlessfun.ButAustraliahasnopredators（捕食者）(23)________(adapt)tokillingrabbitsandnoneofthediseasesthatkepttheirpopulations(24)________controlinEur
5、ope.Thelooserabbitsbredlike,well,rabbits,andbegantotakeoverthecountryside.Withinafewdecades,thereweremillions.By1950,therewere600millionrabbitsinAustralia.Sixhundredmillionhungryrabbitscoulddorealharm.Theycausedmoredamagethananyotherspeciesintroducedtothec
6、ontinent.Theyatenativeplantspecies(25)________theydisappeared.Theycompetedforfoodandshelterwithnativeanimals.theycausedtheextinctionorendangermentofnumerousplantandanimalspecies.Andtheywereanightmareforcattleandsheepfarmers,(26)________animalscouldn'tgeten
7、oughgrasstoeatandstarved.Therabbitsdidsomegood,ofcourse.Theyprovidedfoodforpoorfamilies.Theysupportedfurindustries.Buttheirimpactontheenvironmentandmajorlivestockeconomywastoonegative(27)________(ignore).Peopletriedtrappingthem.Theyevenbuiltahugewallagains
8、tthem.But(28)________(effective)weaponwasavirus.(29)________(test)multipletimes,thedeadlymyxomaviruswasreleasedonAustralia'srabbitsin1950.Thevirushadbeendevelopedverycarefullytoaffectonlyrabbits.Nearly100perc
