谁能帮我解决下这个题呢？

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.  我哪里的答案是B   高手给个解释吧~~我似乎不杂懂

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

原文：

The fact that some fraternal twin pairs look quite different, while
others look quite similar, highlights a very interesting, often
overlooked, feature of fraternal twins, namely that they vary on a
"spectrum" of genetic relatedness. Fraternal twins share half their
genes on average, but members of some pairs share genes for a greater
number of traits than others. It is simply a matter of chance if
fraternal twins inherit the same genes from each parent: Each person
carries two forms of each gene and passes one of them to each child
with a 1/2 probability. Fraternal twins, therefore, have a 50% chance
of resembling or not resembling one another. This same process affects
every one of our genes, and also explains why some siblings resemble
one another in many traits or in only a few.

A. the fact that + 句子 = the fact of + -ing （动名词) ， 正确选项

B. namely 后不应有 that, 其他的都对

C. With some..., a conclusion can be reached that highlights an...  总之选项里 With 后面的又是 it 指代的成分， 莫名其妙

D. With some..., we can see that there might be an interesting and often..., namely a/the considerable variation...

E. Because some..., our study focuses on an interesting and often...

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补充： 我刚开始也认为A不对， 因为我从没有见过 “The fact of +动名词” 这种说法，因为如果是动名词的话就已经本身是一个 fact 了， 属于多余。 而 The fact that 却是非常常见的。

至于B首先 namely 后面要加名词， 所以如果加句子的话可以用 that 引导， 表示一个名词， 就像B开始的部分。 如果是一个动作的话可以用to引导， 比如 They were hardly aware of the challenge facing them, namely, to re-establish prosperity.  因为to 引导的合起来也是名词， 比如 To be or not to be, that's the question.

注意B开头是 That的部分， 是主语，是对的，但是实际上我本人见到的用that引导做主语的只有在非常文绉绉的话语里。我等一下找一句出来。实际上表语从句宾语从句等名词从句都是that 跟后面的东西合起来表一个大名词。

个人认为这种是ManhattanGmat 里面说道的GMAT有的语法对但是读起来别扭的，更何况这句是改别人通顺的句子。

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找到了， 这种that 叫 complementizer .

http://www.cis.upenn.edu/~xtag/tech-report/node88.html

http://en.wikipedia.org/wiki/Subject_(grammar)_

http://www.linguistics.ucla.edu/people/grads/daschuel/SchuelerWCCFL23Paper.pdf

http://www.usc-teresafanego.es/Drift.pdf

http://www.l.u-tokyo.ac.jp/~s_t/clausal_complements.pdf

查了一下http://www.urch.com/forums/gmat-sentence-correction/96556-fraternal-twins-2.html

答案是B，楼主知道到底什么是Official Answer?