Students in fifty schools are to act as guinea pigs for these new teaching methods.

五十所学校的学生将作为这些新教学法的试验对象。

《牛津词典》

For a start, all animals, such as cows, pigs and sheep, always gas limed methane, which is the second most common green house gas after carbon dioxide.

首先，所有的动物，如牛、猪和羊，总是排出石灰甲烷气体，这是继二氧化碳之后第二常见的温室气体。

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It can also cause severe disease in animals such as pigs, resulting in significant economic losses for farmers.

该病毒还可在猪等动物身上引起严重疾病，给养殖者造成重大经济损失。

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In effect, Mac users are acting as guinea pigs for a new way of selling music online.

ECONOMIST: How to pay the piper

Though Nike committed to fair labor practices more than a decade ago, it still faces problems, including a report by the Associated Press last year that workers for its Converse brand in Indonesia were being slapped by supervisors, forced to stand in the scorching sun for hours at a stretch as punishment for not meeting quotas, and insulted as dogs and pigs by bosses.

FORBES: Is Apple's Move To Monitor Factories Enough?

The Judas pig is then fitted with a radio collar or microchip so it can be tracked as it looks for another group of pigs to hang out with.

NPR: $1M Pilot Project Aims To Take Out Feral Pigs