土工合成材料主要功能歸納有六類：即反濾、排水、隔離、()、防護和加筋。
全段圍堰法導流又稱為()。
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
堤防工程竣工驗收前，項目法人應委托省級以上水行政主管部門認定的水利工程()對工程質量進行一次抽檢。工程質量抽檢所需費用由項目法人列資。
在使用割圖功能時：
