选项B最tricky的地方在于contrast the traditional view with a view derived from the 1981 discovery of conodont remains
第二个view本身并不是从1981年的发现中得到的。而是和传统观点一样，在化石发现之前就已经存在了。只是化石的发现解决了两派意见的争端

定位：Teeth were more primitive than external armor according to this view
但根据文末的It now appears that the hard parts that first evolved in the mouth of an animal improved its efficiency as a predator可知，最新的discovery支持了第二种学者的意见conodonts are predator，BE都是传统观点因此错了。剩下的AC在原文中就有直接细节对应

定位：Moreover, whereas P. ochraceus occupies an unambiguous keystone role on wave-exposed rocky headlands, in more wave-sheltered habitats the impact of P. ochraceus predation is weak or nonexistent, and at certain sites sand burial is responsible for eliminating mussels.

D. or前后不平行。。。

外延与内涵

substitute 替代，句意很重要

mark
as much because….as because..并列

vote这件事和deny这件事具有直接的相关性, 所以选to do. 其他都不对

主谓一致 关注主语 what is much more difficult to determine 是单数 不要被表语、宾语影响 除非谓语动词前没有主语

mark

gamt中不用this做形式主语，用it

ing短语growing again需改为不定式短语to grow again，

C选项：复数代词those的指代对象只能为复数名词，这里无法指代正确的比较对象semantic organization。

高亮部分说Anecdotal reports没能分辨清楚decrease属于三种情况里的哪一种；因此明科学家们基于report得出的结论是有问题的

Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past

主题是evaluate these claims

倒装

counting it明显存在问题

Frazier and Mosteller assert that medical research could be improved by a move toward larger, simpler clinical trials of medical treatments.

C选项的问题应该在于beginning 和 后面的evolved不平行吧