13: Dolphins lack vocal cords, nevertheless creating sounds: a complicated system of whistles, Squeaks, moans, trills, and clicks are produced by sphincter muscles inside the blowhole.

A: nevertheless creating sounds: a complicated system of whistles, squeaks, moans, trills, and clicks are produced by

B: nevertheless creating sounds: they produce a complicated system of whistles, squeaks, moans, trills, and clicks with

C: but they do create sounds, producing a complicated system of whistles, squeaks, moans, trills, and clicks being produced

D: but they do create sounds, a complicated system of whistles, squeaks, moans, trills, and clicks being produced

E: but nevertheless creating sounds: a complicated system of whistles, squeaks, moans, trills, and clicks produced by

这道题没有人问过。参考答案是E，可是but 和nevertheless在一起意思表达重复。

D和E是我最先排除的。正确答案应该是B吧

为什么说but 和nevertheless意思重复呢？

按照朗文：

What you said was true but nevertheless unkind.