1、 In the first model,a group of mice were put in a cage with levers that dispensed food.When the mouse pushed a lever,a liquid treat—either a starchy or a sweet liquid—came out.
第一组试验中，一群老鼠被置于一个装有能提供食物的操纵杆的笼子里，当老鼠推动操纵杆的时候，一滴液体食物(含有淀粉或糖的液体)就会掉出来。
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