Ron:
both of them are idiomatically legitimate; they just mean different things.
a plan TO DO X means that people now have the intention of doing X, whereas before they did not.
a plan FOR DOING X means a plan for how to actually execute this action; usually, this construction implies that the intention was already there, but that the plan of execution is new.
错误原因:没有综合全文看,第一段定位句,scientists' reconstructions of the animals' anatomy have had important implications for hypotheses concerning the development of the vertebrate skeleton. 这句是说软体动物的解刨可以帮助下结论,但是题目问的是结论是什么?所以这个定位的地方只是一个大前提。还要往后找。其他提到的科学家有,traditionalists ,paleontologists,传统主义者有个观点说骨骼先于牙,随后古生物学家就说了没有牙那些东西根本不会进化,所以最新的观点(也就是结论)就是牙要比其他的早。Teeth were more primitive than external armor according to this view, and the earliest vertebrates were predators.这句才是结论。而最后一段是作为支持这句的。
E选项:没画marking前,司机都不敢在这些路上开夜车,现在画了marking,他们开始开夜车了,所以事故率就上去了