少数细胞膜表面有膜小凹。

A little part of the surface of cellular membrane had caveola.

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所以字体虽然小，但是凹得很深，而且非常清晰。

Therefore, although the font is small, but very deep concave, but very clear.

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所以字体虽然小，但是凹得很深，而且非常清晰。

Therefore, although the font is small, but very deep concave, but very clear.

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