Themainreasonfor(提示:下文信息重要)thereductioninthedeathrateinthedevelopingworldhasbeenimprovedpublichealthmeasures.Forexample,(提示:下文信息不重要,仅仅是为了用来证明前面的观点)inSriLankathedeathratewashalvedovertenyearsbysprayingthemosquitoeswhichcarrymalaria.
Why(提示:问题的答案中有读者应该关注的重点)isitsoeasytocutthedeathrateinthiswayandyetsohardtoreducethebirthrate?Oneanswer(提示:这只是众多答案中的一种,并不是最重要的。)isthatpublichealthmeasurescanbeverycheap.Anti-malarialsprayingisinexpensive.Butthisisnottheimportantpoint(提示:but后面的是非常重要的信息).Forbirthcontrolprogrammestobesuccessful,achangeinattitudeisrequired,whereasdeathcontrolcanbeachievedautonomously.Inotherwords,(提示:这里是作者想要强调的重要信息)thedeathratecanbecutwithoutanythingelsechanging.