312. There were various views about what constitutes it, but there was agreement that such an essence exists—that is to say, that there is something by virtue of which man is man.

译文　虽然关于人的本质构成有众多观点，但是大家都认同这种本质是存在的，也就是说，人之所以成为人，正是由于某种本质。

点睛　本句是个并列复合句，主干是There were...views..., but there was agreement...。其中，what引导的宾语从句what constitutes it充当介词about的宾语；that引导的同位语从句that such an essence exists对agreement进行了解释；破折号后的内容也是对agreement进行补充说明；that is to say为插入语；by virtue of which man is man 是something的定语从句，先行词something在从句中作宾语。

constitute意为“构成，组成”。如：

Nuclear waste constitutes a serious danger. 核垃圾构成了严重的威胁。

essence意为“本质，实质”。如：

He was the essence of gentility. 他出身高贵。

by virtue of意为“因，靠，由于，借助于”。如：

These people exercise power by virtue of their wealth. 这些人凭借财富而行使权力。

考点归纳　插入语即句子中间插入的一部分，不充当任何句子成分，也不和句子成分发生结构关系，同时既不起连接作用，也不表示语气，删掉后并不影响句子结构的完整性。以下是几类常见的插入语。

用简短的句子结构作插入语，常见的有：I think、I hope、I guess、I believe、I suppose、I wonder、I tell you、I say、I'm afraid、I'm sure、you see、you know、as you know、that is、that is to say、what's more等等，可以置于句中或句尾。如：This diet, I think, will do good to your health. 这类饮食，我感觉会有益于你的健康。

It won't be raining long, I hope. 希望雨不要下太久。

副词或副词短语用作插入语，一般放在句首或句尾。如：

Happily for him, his stepmother was kind to him. 值得为他高兴的是，他的继母对他很好。

You'll be able to pass the coming exam, surely. 你能通过即将到来的考试，一定会的。

介词或介词短语作插入语，一般放在句首，有时也可放在句中。如：

By the way, Bob sends his best wishes. 顺便说一句，鲍勃送上他最诚挚的祝福。

This novel, in some point, is not so attractive. 这本小说从某种程度上来说，并不是很吸引人。

分词短语作插入语。如：

Generally speaking, boys run faster. 通常说来，男孩子跑得更快。

不定式短语作插入语。如：

To conclude, it was a great success. 总结起来，这是巨大的成功。

英语六级阅读