But it's a very,very rare dinosaur,". Though dinosaur researchers have made giant strides in recent years,they know they have much more to learn.

VOA: standard.2009.12.08

Now, I know I'm answering your question I think in a better way, but it's actually very rare.

我想我现在已经很好的回答了你的问题,不过这种情实际上是非常罕见的

耶鲁公开课 - 心理学导论课程节选

So, if you by chance, I know it's very rare, but if by chance you don't get the class you can always follow up later.

如果你们偶然，我知道不太可能，但是如果不小心你们错过了某节课,你们就可以在之后补回来了。

麻省理工公开课 - 固态化学导论课程节选

"Its markings show it's female and it's about the same size as a robin, but it's very rare to see these birds in the UK so it's causing quite a stir, " Mr Oliver said.

BBC: 'Rare' desert wheatear 'accidentally' migrates to Essex

But it's rare to find a plot as extreme as one described by prosecutors in Tennessee.

NPR: Obama Assassination Plot Thwarted

For a 25-year-old to achieve this deeper level of interpretation is not unheard of, but it's rare.

NPR: Yaron Kohlberg: Fighting Schumann's Battles