宾夕法尼亚大学的心理学家进行的动物实验表明，在多次失败之后，大多数动物都会作出这样的结论：情况已无可救药，超出了它们的控制范围。
Animal experiments by psychologists at the University of Pennsylvania had shown that after repeated failures, most animals conclude that a situation is hopeless and beyond their control.
动物实验表明它基本是安全的。
动物实验表明，该物质会诱发肺癌，但相关人类研究还缺乏相关证据。
Animal studies have shown that glass wool fibers cause lung tumors, but there is little evidence from human studies of a risk.
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