上星期我朋友的公司出現了一起風波。一名會計被發現挪用公款。他連續幾個月沒被發現，因為他做得很隱蔽。我們可以用一個習慣用語來形容他的這種做法。那就是: cover one's tracks.

Cover意思是隱瞞，掩飾，tracks軌跡。連起來，to cover one's tracks, 意思就是掩蓋行蹤，隱瞞證據。上面的例子中，the accountant was able to cover his tracks for a long time before his scheme was finally discovered. 這位會計長期隱瞞證據，直到他的陰謀被發現。

下面的例子里，一名罪犯越獄之后是如何掩飾自己行蹤的呢? 我們趕快來聽聽看:

例句-1：The prisoner escaped weeks ago. The police had a hard time finding her because she covered her tracks. She was careful not to use her real name and she kept traveling from one state to another. When her photo appeared on TV, a viewer reported seeing her. And she was finally captured.

這段話意思是說：這名犯人幾星期前越獄，警方費了好大力氣搜捕她，但是她很好地掩蓋了自己的行蹤。她不使用真名，而且不停在州與州之間轉移。直到她的照片被公布在電視上，有人舉報說曾經見過她，才終于把她抓了回來。

現在高智商犯罪真是越來越普遍! 很多犯罪分子不但聰明，還會利用高科技手段來掩蓋自己的所作所為。我還記得前幾年大熱的美劇: Prison Break 《越獄》，里面的男主角Michael就是這樣，He was able to cover his tracks with a complicated underground maze. 他挖了一條復雜的地下迷宮來掩飾行蹤。

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大家都喜歡驚喜派對。下面的這個例子里，兄妹倆人為了給他們的媽媽制造一個驚喜派對，一直試圖掩飾他們的計劃。讓我們來聽聽看他們都做了些什么:

例句-2：Mom and dad have no idea that we're organizing a party to celebrate their 50th wedding anniversary. So far we've been pretty good at covering our tracks. If we let them think that we and the other guests have other plans that weekend, they won't find out what's really happening. Then it'll be a big surprise!

這段話是說：媽媽和爸爸完全不知道我們為他們50周年結婚紀念日準備了一場派對。到目前為止，我們的掩飾工作做得還不錯。如果我們能讓他們以為大家在那個周末都有別的安排，他們就完全不會知道我們真正的計劃。那就真是個大驚喜了!

所以說，cover one's tracks也不一定都是干壞事。我同事有一次也給了我這樣一個驚喜。他們計劃了一次特別的午餐會慶祝我晉升，但是卻騙我說這是一次編輯會。They carefully covered their tracks so I didn't find out about the surprise lunch party! 他們小心掩飾，所以我一點也沒發現，原來那是一次驚喜午餐會!