And,Mister Hellsten says, genetic changes are rare for frogs, humans and most organisms.

VOA: special.2010.06.29

It is very rare, for instance, for somebody who has learned English past puberty to speak without an accent.

比如,在青春期后才学习英语的人,很少有讲英语是没有口音的

耶鲁公开课 - 心理学导论课程节选

It's perfectly fine, but they envy us for our finite lifespans, because what we've got and they don't have is something that's for each individual rare-- something that's not lasting, something that's precious in that way.

不朽很好，但他们羡慕我们的有限寿命，因为我们有而他们没有的是,对每个人来说稀有的东西-,不会永远持久的东西，从那个层面讲珍贵的东西。

耶鲁公开课 - 死亡课程节选

"Those opportunities are very rare for filmmakers, so I felt a responsibility to try and do something memorable with it."

VOA: standard.2010.07.16

(HAPPY BIRTHDAY SONG) It used to be rare for people to live to 100.

VOA: standard.2010.04.08

The event,on July sixteenth, was a rare chance for planetary scientists to share with the public the mysteries of Mars.

VOA: special.2010.07.28

It is also not rare,she says, for the perpetrator to be an uncle, cousin or other family member.

VOA: standard.2010.06.29

On Wednesday,North Korea extended a rare apology to the South for a flood it unleashed last month.

VOA: standard.2009.10.15

Determining Muse's true age is difficult because birth certificates are rare in Somalia,a country which has not had a functioning government for nearly two decades.

VOA: standard.2009.04.22

(Sound) Soung Ma earns money taking tourists for a rare glimpse of the dolphins.

VOA: standard.2010.01.11

Leavitt says some collectors will pay thousands of dollars for a rare orchid.

VOA: standard.2010.02.21

As the groundbreaking Right to Education law came into effect Thursday, Prime Minister Manmohan Singh made a rare address to the nation to express his government's commitment to ensuring education for all children.

VOA: standard.2010.04.01