中国大学MOOC:NobodyreallyknowshowbigLagosis.Whatsindisputableisthatitsgrowingveryquickly.Betweennowand2050,theurbanpopulationofAfricacouldtriple.Yetcitiesinsub-SaharanAfricaarenotgettingricherthewaycitiesintherestoftheworldhave.MosturbanAfricansliveinslums（贫民窟）;migrantsareoftennotmuchbetteroffthantheywereinthecountryside.Why?Theimmediateproblemispoverty.MostofAfricaisurbanisingatalowerlevelofincomethanotherregionsoftheworlddid.Thatmeansthereslittlemoneyaroundforinvestmentthatwouldmakecitiesliveableandmoreproductive.Withoutupgradesandnewcapacity,bridges,roadsandpowersystemsareunabletocopewithexpandingpopulations.WiththeexceptionofSouthAfrica,theonlylightrailmetrosysteminsub-SaharanAfricaisinAddisAbaba,Ethiopia.Trafficjamleadstoexpenseandunpredictability,thingsthatkeepinvestorsaway.Inotherpartsoftheworld,increasingagriculturalproductivityandindustrialisationwenttogether.Moreproductivefarmersmeanttherewasasurplusthatcouldfeedcities;inturn,thatcreatedapooloflabourforfactories.ButAfricancitiesaredifferent.Theyaretoooftenbuiltaroundconsumingnaturalresources.Governmentisconcentratedincapitals,soisthemoney.MosturbanAfricansworkforasmallminorityoftherich,whotendtobeinvolvedineithercronyish（有裙带关系的）businessesorpolitics.SinceAfricanagricultureisstillbroadlyunproductive,foodisimported,consumingaportionofrevenue.Sowhatcanbedone?ThoughAfricancountriesarepoor,notallAfricancitiesare.InLagos,foreignoilworkerscanpayasmuchas65,000dollarsperyearinrentforamodestapartmentinasafepartoftown.Ifthatincomewerebettertaxed,itmightprovidetherevenueforbetterinfrastructure.Ifcityleadersweremoreaccountabletotheirresidents,theymightfavourprojectsdesignedtohelpthemmore.Yetevenasnewroadsarebuilt,newpeoplearrive.Whenacityspopulationgrowsby5%ayear,itisdifficulttokeepup.46.Whatdowelearnfromthepassageaboutcitiesinsub-SaharanAfrica?A.Theyhavemoreslumsthanothercitiesintheworld.B.Theyaregrowingfastwithoutbecomingricher.C.Theyareasmodernisedasmanycitieselsewhere.D.Theyattractmigrantswhowanttobebetteroff.47.Whatdoestheauthorimplyabouturbanisationinotherpartsoftheworld?A.Itbenefitedfromthecontributionofimmigrants.B.Itstartedwhenpeoplesincomewasrelativelyhigh.C.Itbenefitedfromtheacceleratedriseinproductivity.D.Itstartedwiththeimprovementofpeopledlivelihood.48.Whyissub-SaharanAfricaunappealingtoinvestors?A.Itlacksadequatetransportfacilities.B.Thelivingexpensestherearetoohigh.C.Itisonthewholetoodenselypopulated.D.Thelocalgovernmentsarecorrupted.49.InwhatwaydoestheauthorsayAfricancitiesaredifferent?A.Theyhaveattractedhugenumbersoffarmlabourers.B.Theystillrelyheavilyonagriculturalproductivity.C.Theyhavedevelopedattheexpenseofnature.D.Theydependfarmoreonforeigninvestment.50.WhatmightbeasolutiontotheproblemsfacingAfricancities?A.Loweringofapartmentrent.B.Bettereducationforresidents.C.Morerationaloverallplanning.D.Amoreresponsiblegovernment.

【填空题】用 logspace 函数创建向量 A= [10 2 ,10 2.2 ,10 2.4 ,10 2.6 ,10 2.8, 10 3 ,10 3.2 ,10 3.4 ,10 3.6 ,10 3.8 , 10 4 ,10 4.2 ,10 4.4 , 10 4.6 ,10 4.8, 10 5 ,10 5.2 , 10 5.4 , 10 5.6 ,10 5.8 ,10 6 ,10 6.2 ,10 6.4 ,10 6.6 ,10 6.8, 10 7 ,10 7.2 ,10 7.4 ,10 7.6 ,10 7.8 ,10 8 ] 的语句是___________

求下列函数的定义域/ananas/latex/p/3282031: (-∞,-10)∪(10,+∞)|(-∞,-10]∪(10,+∞)|(-∞,-10]∪[10,+∞)|(-∞,10]∪(-10,+∞)

自发突变率是很低的，一般为（）。 A: 10～10 B: 10～10 C: 10～10 D: 10～10

Тывсегдаопаздываешьичастоприходишьнаурок_____(за10минутдоначала,за10минуткначалу,через10минутпосленачала).

大学物理C期末考试的时间是 A: 2020.07.13 10:10~12:10 B: 2020.07.13 15:10~17:10 C: 2020.07.14 10:10~12:10 D: 2020.07.14 15:10~17:10

Java语言具有跨平台技术是因为（ ）。 A: "10/10/02" B: 10/10/02 C: {10/10/02} D: #10/10/02#

【单选题】下列程序的运行结果是: print(10 and 20) print(20 and 10) print(10 or 20) print(20 or 10) A. 20 10 10 20 B. 20 20 10 10 C. 10 20 10 20 D. 20 10 20 10

正常成年男性红细胞、血红蛋白、白细胞的正常参考值的描述，下列哪项是正确的（） A: 3.5×10／L~5.0×10／ B: 110~150g/ C: 4×10／L~10×10／L D: 4.0×10／L~5.5×10／ E: 120~160g/ F: 4×10／L~10×10／L G: 4.0×10／L~5.0×10／ H: 120~160g/ I: 4×10／L~10×10／L J: 4.0×10／L~5.5×10／ K: 110~150g/ L: 4×10／L~10×10／L M: 4.0×10／L~5.5×10／ N: 110~160g/ O: 4×10／L~10×10／L

坐标方位角是10°10′则它的坐标象限角是（ ）。 A: 10°10′ B: 190°10′ C: 260°10′ D: -10°10′