文本内容:
托福综合写作范文举例加氟自来水力口氟自来水adding fluoridein publicwater reading在自来水中加氟的好处.防止蛀牙
1.杀死细菌
2.对骨骼有好处3decrease bonediseases lecture反驳.自来水并不会留在口中,对防止蛀牙没有帮助
1.氟会与输水管中的化学物质反应,产生有毒物质,其危害大于细菌2water pipe浏览过程中如有任何问题.欢迎点击咨询«.过量的氟会使骨骼变脆3例文The speakerrefutes thereadings argumentabout thebenefits ofadding fluoride to pipewater byproviding contradictoryevidence aboutpipe watersfluoride seffectivenessin preventingcavities inteeth,killing bacteria,and decreasingbon ediseases.First,the speakerpoints outthat theshort contactof fluoridewith teethwill notenable thefluoridetoprevent cavities,as thereading argues.Instead,the waterwillpass themouth andteeth quicklyand godirectly tothe stomach.Another argumentraised in the lectureis that fluoride couldundergo chemicalreactions withheavy metalsinthepipe,such aslead.This willcreate toxicsubstances whichwill poseserious healththreat.In thisway fluoridecould beeven moredeadly thanbacteria.Although thefluoride,as thereading says,will killsome bacteria,the curehere isworse thanthe disease.In theend,the speakermaintains thatoverdose offluoride willbackfire to human bones.Although thereading illustratesthatfluoridewill improvebone strength,the lecturesays overdosewill causeserious damagetohumanbones.。