请教 gwd-15-18

Q18:

A new study suggests that the conversational pace of everyday life may be so brisk it hampers the ability of some children for distinguishing discrete sounds and words and, the result is, to make sense of speech.

1. it hampers the ability of some children for distinguishing discrete sounds and words and, the result is, to make
2. that it hampers the ability of some children to distinguish discrete sounds and words and, as a result, to make
3. that it hampers the ability of some children to distinguish discrete sounds and words and, the result of this, they are unable to make
4. that it hampers the ability of some children to distinguish discrete sounds and words, and results in not making
5. as to hamper the ability of some children for distinguishing discrete sounds and words, resulting in being unable to make

答案是D，为什么不是B?

我自己知道了。本题考Parallel

A new study suggests that the conversational pace of everyday life may be so brisk that it hampers the ability of some children
      to distinguish discrete sounds and words and, as a result, to make sense of speech

是说children - to distiguish... and to make sense of...的能力。

D的错误在于把results与hampers平行了，这样就变成conversational pace是主语，results making sense of speech...

逻辑主语不对，意思不通。