请教 GWD 7-16 namely that ?

Q16:

The fact of some fraternal twins resembling each other greatly and others looking quite dissimilar highlights an interesting and often overlooked feature of fraternal-twin pairs, namely they vary considerably on a spectrum of genetic relatedness.

A.   The fact of some fraternal twins resembling each other greatly and others looking quite dissimilar highlights an interesting and often overlooked feature of fraternal-twin pairs, namely they vary considerably

B.    That some fraternal twins resemble each other greatly while others look quite dissimilar highlights an interesting and often overlooked feature of fraternal-twin pairs, namely that they vary considerably

C.   With some fraternal twins resembling each other greatly and others looking quite dissimilar, it highlights an interesting and often overlooked feature of fraternal-twin pairs, namely considerable variation

D.   With some fraternal twins resembling each other greatly and others looking quite dissimilar, it is a fact that highlights an interesting and often overlooked feature of fraternal-twin pairs, namely a considerable variation

E.    Because some fraternal twins resemble each other greatly and others look quite dissimilar, this fact highlights an interesting and often overlooked feature of fraternal-twin pairs, namely they vary considerably

   Answer: B

选B没问题，但B中 “ , namely that 。。。” 如何理解？ 我的理解是：that they vary considerably 是 feature 的同位语， namely 是副词可以去掉，那么that前的逗号应是错的吧?

参考Longman关于namely的解释:

namely:

used when saying the names of the people or things you are referring to

- Three students were mentioned, namely John, Sarah and Sylvia.

A: omits "that" after "namely", a run-on sentence with two subjects and two verbs, 'highlights' and 'vary'

E: Because + clause, ( this fact ) cannot refer to ( because + clause )

这种题的思路是什么啊?看到题完全傻眼~~~

思路思路

rhod说fact是多余，是不是ets出题的规律呢？我就是感觉wordy

因为B比A简洁就选B

回楼上：结构：That.....（主语） highlights ....and  overlooked

ps：hightlight和overlook的时态不同，og中有类似的例句没？谢谢~

interesting and often overlooked 应该都是feature的定语吧.

同意！！