错选c,没有认真读题:
because these sediments are composed of calcium carbonate shells of marine organisms, shells that were constructed with oxygen atoms drawn from the surrounding ocean. 并不是说shell are found only in areas that were once covered by land ice, land ice明显错误。
shells that were constructed with oxygen atoms drawn from the surrounding ocean.
所以选E
Second, it is a more continuous record than that taken from rocks on land.
选项b It had far more gaps in its sequence than the record taken from rocks on land.
重点是对应文中哪里
真TM不明白为什么不能是重量在中间,非得是DISCUS