GWD6-19

Q19:

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.

1. 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
2. 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
3. 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
4. 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
5. 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

请NN，指点下为啥B对阿。我不理解。谢谢

要注意这里overlooked是形容词，句子的结构 that从句(主语)... highlights(谓语).....

那句子要表达的意思是：

That some fraternal twins
                    resemble each other greatly while others look quite dissimilar
                highlights an interesting, 也highlights 那种经常被忽略的fraternal-twin pairs的特点：they vary considerably on a spectrum of genetic relatedness.

这是我的理解，欢迎其他人讨论~~