Closed to outsiders for five decades, Burma, also known as Myanmar, is something of an unknown quantity, particularly in terms of its natural riches.

请问：句中的is something of是什么意思？

回答如下：在弄清楚这个短语之前必须先弄清楚单词详细用法，这个单词详细用法如下。

根据“用法5”我们可以知道：

is something of+名词 表示 有点儿..../有几分...

an known quantity意思是 难以预测的人〔事〕 

例如：To her the outside world was a totally unknown quantity. 对她来说, 外部世界完全是个未知数。

因此 is something of an known quantity 意思是：有几分/有点儿难以预测的事情/地方

附something用法详解：

［用法1］某物，某事(指事物、情况、事件、想法等)

He realized right away that there was something wrong.

他马上意识到什么地方出了问题。

There was something vaguely familiar about him.

他身上有着某种似曾相识的东西。

The garden was something special.

这个花园很特别。

'You said there was something you wanted to ask me,' he said politely.

“您说过有事要问我，”他彬彬有礼地说。

There was something in her attitude that bothered him.

她的态度里有某种东西让他感到不安。

People are always out in their cars, watching television or busy doing something else.

人们总是驾车外出，或者看电视，再不就是忙点其他什么事情

［用法2］(描述、数量等)大概，大致，大约，左右

He described the smell as something between a circus and a seaport.

他形容那种气味介于马戏团和海港的味道之间。

Clive made a noise, something like a grunt.

克莱夫发出一种声响，像是咕哝了一句。

There was something around a thousand dollars in the office strong box.

办公室的保险柜里大约有 1,000 美元。

Their membership seems to have risen to something over 10,000.

他们的会员似乎已经增加到约 1 万名以上。

［用法3］(人、物等)真棒，很了不起（something or is really something）

You're really something

 你真了不起。

The doors here are really something, all made of good wood like mahogany.

这些门真是极品，全部由红木一类的优质木材加工而成。

This is really something. Someone actually thinks my records are all right!

太棒了，有人真的认为我的唱片不错呢!

［用法4］聊以自慰的事;还算幸运的事（'that's something'）

Well, at least he was in town. That was something.

好啦，至少他在城里，还算幸运。

Well, you're staying. That's something I suppose.

啊，你准备留下来了。我想这算是能够聊以自慰吧。

［用法5］有点儿;有几分(something of +名词)

The city proved to be something of a disappointment.

结果这座城市有点儿令人失望。

She received something of a surprise when Robert said that he was coming to New York.

当罗伯特说他就要来纽约的时候，她有点吃惊。

He is something of a fighter, and will certainly want to win.

他可谓是一个斗士，当然想赢。

［用法6］不定代词(想法或建议)有道理，值得考虑（something in sth）

Christianity has stood the test of time, so there must be something in it.

基督教经受住了时间的考验，因此其中一定是有些道理的。

There had been something in Des's first statement.

德斯最初的陈述有些道理。

Could there be something in what he said?

他的话会不会有些道理呢？

［用法7］不定代词(表示对说的话不能肯定)或别的什么，或诸如此类（'or something' and 'or something like）

This guy, his name was Briarly or Beardly or something.

这个家伙叫布赖厄利、比尔德利或什么类似的名字。

The air fare was about a hundred and ninety-nine pounds or something like that.

机票 199 英镑左右，大概是这个价钱。