A diesel can be spotted in one of the tree series, although it takes a while to make it out.

花点力气，就会发现一系列树画的其中一幅画有一部柴油机。

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It was certainly unknown, in 1961, to Sheila Michaels, a 22-year-old civil rights worker in New York City, who one day spotted it on a piece of mail that her roommate received.

在1961年的某一天，纽约市的一位民权工作者Sheila Michaels在室友收到的一封信上发现了这个词，但当时她对这些情况还一无所知。

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This was spotted in 2004 to much fanfare; but no one has seen it since.

这种鸟于2004年被发现并引起了广泛关注，但是从那以后就再也没有被看到过了。

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And when air traffic controllers radioed other pilots in the area and asked them to look out for the flying object, no one else spotted it.

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The subscriber, Vox Media marketing director Callie Schweitzer, thought the photo was a public one when she spotted it in her newsfeed.

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Clarke spotted it one day.

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