As a way of reconciling these two facts, scientists have hypothesized that nearly all of the oxygen being produced was taken up by iron on Earth's surface.

为了调和这两个事实，科学家们假设，几乎所有产生的氧气都被地球表面的铁吸收了。

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The color changes are executed by two different kinds of cells in the octopus' skin, mainly by color cells on the skin's surface call chromatophores.

颜色的变化是由章鱼皮肤上的两种不同的细胞造成的，主要是皮肤表面的色素细胞。

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Two electrodes that measure changes in the body's surface moisture are attached to the palms of your hands.

测量体表湿度变化的两个电极被连接到你的双掌上。

《柯林斯英汉双解大词典》

It recommended using geometric lines of latitude and longitude to convey a three-dimensional Earth on a two-dimensional surface, and it included the co-ordinates of over 8, 000 locations in the ancient world.

ECONOMIST: There is no such thing as an objective map

Picture what it would be like to roll a bowling ball onto the two-dimensional surface of a trampoline.

NPR: Einstein: Relatively Speaking, a Complicated Life

They flew on two suborbital and four Earth-orbital Mercury launches, nine Earth-orbital Gemini flights, two Earth-orbital Apollo tests, and two lunar-orbital tests that made those lunar surface landings possible.

FORBES: Neil Armstrong's Immortal Footprint