The running wheel of the control group was fixed.

跑笼固定不转。

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Feig and colleagues raised mice, some in plain cases with wood chips and others in "enriched" cages with boxes, a running wheel, toys, and constant rearrangements of nesting material.

菲格及其同事分别在装有木屑的普通盒子和放有盒子、飞轮和玩具等物品的“高级”笼子中培育两组幼鼠。在后一个环境中，研究人员还不停地变换物品的摆放。

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Or, you can choose to keep working non-stop like a hamster running on a wheel that keeps going faster and faster.

CNN: Take your vacation, or die?

"Enough hamsters running on a wheel could displace a power plant, but no one's going to do it, because it's too expensive, " he says.

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The open-wheel series is running a second, full-length race in the same weekend for the first time Sunday when Conway will start up front for the first time in his career.

NPR: Conway Wins 1st Of 2 Races At Detroit Grand Prix