Sugarissomuchapartofourmodernlifethatweonlyreallythinkaboutitwhen,forsomereason,wecannotobtainit.
Ithasbeenknowntomanforatleast3,000years,buthascomeintocommonuseonlyinmoderntimes.
Untilquiterecentlyitwasconsideredasamedicineandasaluxuryfortheveryrichonly.
Sugaris,then,veryimportanttoourcivilization.
Ofcoursemostofusrecognizesugarimmediatalyasthesweetmaterialwhichweputincoffeeorcakes.
Thiscommonformofsugarisderivedfromtwoplants;thesugarcaneandthesugarbeet.
Butthereareinfactmanytypesofsugar,andthechemistrecogniseshundredsofdifferentvarieties,eachcomingfromadifferentsource.
About90%ofthesugarisproducedasfood.
Only10%isusedinindustryforpurposesotherthanfoodproduction.
Yetsugarhasgreatpossibilitiesforuseasthebasisofchemicals.
Itcanevenbeusedformakingplastics.
Inthefuturethesepotentialuseswillcertainlybedevelopedmorethaninthepast.
Questions11to13arebasedonthepassageyouhavejustheard.