土方施工准备技术要点有哪些?
什么是负载测试?什么是性能测试?
瓶装乙炔气与乙炔发生器相比具有哪些显著优点?
Thefoodweeatseemstohaveprofoundeffectsonourhealth.Althoughsciencehasmadeenormousstepsinmakingfoodmorefittoeat,ithas,atthesametime,mademanyfoodsunfittoeat.Someresearchhasshownthatperhapseightypercentofcancerisrelatedtothedietaswell,especiallycancerthecolon.Differentculturesaremorepronetocontractcertainillnessesbecauseofthefoodthatischaracteristicinthesecultures.Thatfoodrelatedtollnessisnotanewdiscovery.In1945,governmentresearchersrealizedthatitratesandnitrites,commonlyusedtopreservecolorinmeats,andotherfooddditives,causedcancer.Yet,thesecarcinogenicadditivesremaininourfood,nditbecomesmoredifficultallthetimetoknowwhichthingsonthepackginglabelsofprocessedfoodarehelpfulorharmful.Theadditiveswhichweeatarenotallsodirect.Farmersoftengivepenicillintobeefandpoultry,andbecauseofthis,penicillinhasbeenfoundinthemilkoftreatedcows.Sometimessimilardrugsareadministeredtoanimalsnotformedicinalpurposes,butforfinancialreasons.Thefarmersaresimplytryingtofattentheanimalsinordertoobtainahigherpriceonthemarket.AlthoughtheFoodandDrugAdministration(FDA)hastriedrepeatedlytocontroltheseprocedures,thepracticescontinue.
48.Whatisthemaintopicofthepassage?
A.Foodandourhealth
BFoodandadditives
C.Foodandcancer
DFoodandculture
49AllofthefollowingstatementsaretrueEXCEPT_______.
AFortypercentofcanceriscausedbyproblemsrelatedtofood.
BResearchershaveknownaboutthepotentialdangeroffoodadditivesformanyyears
C.Weeatsomeofthefoodadditivesdirectlyandsomeindirectly
DDrugsarealwaysgiventoanimalsformedicinalpurposes
50.Whydofarmersgivedrugstotheiranimals?
A.tospeedupthegrowthofanimals
BTomaketheanimalsfatter
Ctomaketheanimals’meatfittoeat
DTomaketheanimals’meatrichinnutrients
51.Itcanbeinferredfromthepassagethat_________.
Ascientisthavemadeallthefoodfittoeat
Bonlyinrecentyearshavepeoplefoundthatthefoodisrelatedtoone’sillness
Callkindsofcancerarerelatedtothediet
Dsomeadditivesareharmfultoourhealth
52.Theword“this”inthesecondsentenceofparagraph2mostprobablyrefersto__________.
Afarmer
Bpenicillin
Cbeefandpoultry
Dthefactthatfarmersoftengivepenicillintoabeef
施工安全措施编制的原则?
结构工程材料质量的基本要求有哪些?
Python语言有哪些运算符?请列表说明它们各自的运算优先级。
什么是数据库的安全性?
水利工程灌浆按作用分为哪几种?其作用分别是什么?
某桥为20+3×25+20m钢筋混凝土连续箱梁桥,采用满堂式钢管支架现浇。
问题:
1、通常处理地基的方法有哪些?
2、如何设置该桥的常见质量控制点?
3、为防止该桥出现构造裂缝,对原材料和模板有何要求?