They are too old and Africa is too hot for significant traces of the molecule to have survived.

因为这些化石太古老，加上非洲太炎热，无法找到分子存活的明显痕迹。

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While it can seem that the city is intent on stream rolling over its past, you can still see traces of old Edo.

即便这个城市热心踩着它的过去走向未来，你却依然能看到古江户的痕迹。

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For example, 100-year-old bird skins are being used today to piece together a record of avian flu, as the feathers retain traces of toxins.

例如，100年前的鸟皮如今正在被用来拼接出一个禽流感的记录，因为羽毛中保留毒素的痕迹。

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Though in recent decades the final traces of the grand old days of mahogany dining cars and dinner-jacketed waiters serving up turtle soup have vanished, the line still makes for an adventure worthy of any Grand Tour, particularly with your own diminutive passengers in tow.

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At least those old news reels had traces of the audible static of old magnetic sound recording to remind you that the pictures in front of you were actually moving.

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In The Code Book: The Evolution of Secrecy from Mary, Queen of Scots, to Quantum Cryptography, due out soon from Doubleday, British author Simon Singh traces the evolution of the centuries-old battle between code writers and code breakers.

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