It isn't actually known how many sites there are across Australia where rock art can be found—but unfortunately, we do know that much of the art is being lost to us.

目前还不知道在澳大利亚有多少地方能够发现这种岩石艺术；但不幸的是，我们知道有很多艺术作品正在消失。

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They may not be well-known to the public, but they do what they can to help improve people's lives as well.

他们可能不为公众所知，但是也尽其所能地帮助改善人们的生活。

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If they do not, doctors' surgeries may be flooded with what have come to be known as the worried well, and regulation is sure to follow.

如果他们不这样做，医生的的诊室里可能将充斥着将被诊断为恐惧症的病理，而调控也肯定会跟进。

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Tanya Pinto says you do not have to be wealthy or well known to help others.

VOA: special.2009.08.10

Personality-related characteristics, however, take much longer to be known and do not play a more substantial role until later in the relationship, she said.

BBC: NEWS | Health | Similarity 'makes happy marriage'

Officials are known to be keen to do a deal similar to the one that Manchester City struck with Manchester City Council after the Commonwealth Games in 2002.

BBC: Deadline set for 2012 London Olympics stadium bids

If no one can think of what to do then throw out a known to be bad idea and then watch as this sparks better ones.

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