Now, let's work with contrast. For example, The dogs'd eat the bones, and The dogs'd eaten the bones, are so close in sound, yet so far apart in meaning, that

you need to make a special point of recognizing the difference by listening for content.

上句是美国人写的语音书中的一段话，显然，"... are so close in sound, yet so far apart in meaning,..."这2句是平行结构，对称的， 那为什么前半句close是形容词，而后半句so far apart都是副词呢？

in sound和in meaning对称，are so close(adj) 和 (are省略) so far apart (adv) 如何平行对称呢？