'I have eaten' is the present perfect tense of the verb 'to eat', 'I had eaten' is the past perfect and 'I will have eaten' is the future perfect.

I have eaten是动词eat的现在完成时；I had eaten是过去完成时；I will have eaten是将来完成时。

《牛津词典》

Ihad finished 'is an example of the past perfect.

“我过去已经完成了”是过去完成时态的一个例句。

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B. Fill in the blanks with the past perfect or simple past tense of the verbs in brackets.

试用括号里动词的过去完成时态或一般过去时态来填充空格。

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In Citizen Kane, sort of myth of the past is sort of wonderful, perfect childhood playing the snow.

在《公民凯恩》中，过去之谜很精彩,完美的童年，像小孩在玩雪。

麻省理工公开课 - 电影哲学课程节选

Not with this girl, this girl is perfect. But in the past, I've had lots of problems with roommates.

和这个女孩没吵过，她太完美了。但在过去，我和室友之间存在很多问题。

布鲁克林的房价 - SpeakingMax英语口语达人

One from the past that was pitch perfect was the Telegraph running a story on how the US had plans to invade Canada in 1940.

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But for Mourinho, the past ten days are the perfect microcosm for his brilliant, but often unpredictable coaching career.

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He snatched the ball and slid his penalty past Helton to provide the perfect finale to a wonderful night for Wenger's side.

BBC: Arsenal 5-0 Porto (6-2)