All animals take the surgery ear by the right ear, the left ear (opposite side) takes the internal comparison.

所有动物均以右耳作为手术耳，左耳(对侧)作为内部对照。

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By comparison, getting a conventional internal-combustion engine to burn hydrogen instead of petrol is relatively easy.Even so, such efforts have also come to naught.

相比之下(这里应该是指相比于制造氢燃料电池)，将传统内燃机由烧油改为烧氢气要容易一些。即使是这种尝试也没有结果。

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Researchers found that learning to compete against internal benchmarks rather than focusing on comparison with others improved younger player's initiative and motivation.

研究人员发现，学会将自身作为参照物进行比较，而不是专注于和其它人的竞争，这对提高年轻队员的主动性和积极性有很大的帮助。

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We consider non-GAAP international revenues as a useful metric as it facilitates management's internal comparison to our historical performance.

ENGADGET: Google's Q4 2011 results: $2.71 billion profit, $8.13 billion in revenue, Wall Street disappointed