[多项选择]把食物给动物的时候，它会流涎。在给予食物之前不久，如果反复出示铃铛，动物听到铃声就开始流涎，即使不提供食物也是如此。只要铃声伴随着食物的试验反复进行，反应的时间就会减少。这一过程被称为条件反射作用，伴随着铃声的流涎叫做条件反射。如果多次出示铃铛却不让食物紧接着出现，条件反射要么自然而然地产生，要么就会失效。

参考答案:When an animal is presented with food, it will salivate. If a bell is repeatedly presented shortly before the food is administered, the animal will begin to salivate soon after the sound of the bell, even if the food is not offered. With repeated trials of the bell followed by the food, the latency of the response decreases. This process is called conditioning, and salivation to the sound of the bell is termed the conditioned response. The conditioned response may be unlearned or extinguished if the bell is presented a number of times without being followed by food.