The dog scratched itself behind the ear.

狗用爪子挠挠耳后。

《牛津词典》

The most barren region was behind the ear, with a median diversity of 15 species. In comparison, the forearm teemed with a median 44 species.

细菌贫瘠区时耳朵背面，细菌种群的中位数是15，而在前臂是44。

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"Life will change when they open the Sphinx," he said, and added that the Sphinx will open somewhere behind the ear, but he can't remember exactly where.

生命就在他们打开狮身人面像开始改变，他说道他又补充到狮身人面像的开关是在耳朵后面的一个地方，但是他记不清正确的位置在哪里。

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She went over to check it out and found a big red lump behind the ear.

CNN: But is it really an emergency? When to take a child to the ER

The MDHearingAid also sits behind the ear with a plastic dome in the ear canal.

WSJ: Testing, Testing...Can You Hear Better Now?

The Bonebridge is surgically fitted under the skin to the bone structure behind the ear.

BBC: bonebridge