Why is it so rare?

为什么它这么罕见呢？

youdao

It remained hidden for so long because it's so rare.

它被藏了这么久，因为它太稀有了。

youdao

It doesn't necessarily explain how it became so rare, but it explains why it doesn't increase.

这不一定能解释它如何变得如此罕见，但解释了它为什么不增加。

youdao

"What makes it so rare is that it is highly endangered in the wild, in Sumatra, and it is so hard to get to bloom in cultivation."

VOA: standard.2010.07.30

One reason it's been harder to identify stem cells is that they're so rare; the other reason is that it's hard to identify the characteristics of them and it's taken many years to work this out.

干细胞难以识别的原因之一是,这些细胞很少,另一个原因就是,干细胞的特征性蛋白难以识别,我们花了好多年去解决这个问题

耶鲁公开课 - 生物医学工程探索课程节选

It's like rare, so everybody always go to the beach.

这么晴朗的日子不多见，每个人都会想去海边。

强力推荐 - SpeakingMax英语口语达人

And those that did were so rare that they were practically impossible to find.

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So rare it seems virtually impossible and should be nothing to build false hope on.

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No wonder firms that send you away with a smile on your face are so rare.

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