Over and over again, if you put the bell and the food together, pretty soon, the bell will generate saliva.

如果你一再让铃声和食物同时出现，很快，铃声便会促使唾液分泌。

youdao

Over and over again, if you put the bell and the food together, pretty soon, the bell will generate saliva.

如果你一再让铃声和食物同时出现，很快，铃声便会促使唾液分泌。

youdao