GRE阅读文章的第三种常见结构是现象解释型。
文章开始提出一个现象,然后解释现象。解释是主题。有多个解释时,作者一般对前面的解释持负面评价,对最后的解释持正面评价。提出现象时的标志词有:phenomenon, fact; problem, difficulty, puzzle, question等。例如,
What causes a helix in nature to appear with either a dextral twist or a sinistral twist is one of the most intriguing puzzles in the science of formWhat mechanisms, control handedness and keep left-handedness rare?
It would seem unlikely that evolution should discriminate against sinistral snails if sinistral and dextral snails are exact mirror images, for any disadvantage that a sinistral twist in itself could confer on its possessor is almost inconceivable. But left- and right-handed snails are not actually true mirror images of one another
But this evolutionary mechanism combining dissymmetry, anatomy, and chance does not provide an adequate explanation of why right-handedness should have become predominant
Here, the evolutionary theory must defer to a theory based on an explicit developmental mechanism that can favor either right- or left-handednessThus, the path to a solution to the puzzle of handedness in all snails appears to be as twisted as the helix itself.
是什么样的原因致使自然界中的螺旋体呈现出右旋或左旋?这是形态科学中一个最引人入胜的不解之谜....。。究竟是一些什么样的机制控制着旋转方向,并使左旋的比例为数稀少呢?
【GRE阅读有哪些常见结构】相关文章:
最新
2016-03-01
2016-03-01
2016-03-01
2016-03-01
2016-03-01
2016-03-01