It’s known to all that foods have their own savour. Some are sweet， and some bitter. Some smell good， and some terrible①. Having a taste of a certain food， we can know how delicious it is. And we may also probably know what kind of food it is by smelling it. But， what makes us learn the savour② of food？ It’s the sense of taste and the sense of smell that help us know it.
The sense of taste and the sense of smell work together as we eat. The taste buds on our tongues have nerve receptors③ in them. They can respond to only four different tastes—sweet， sour， salty， and bitter. All the other hundreds of tastes come from how foods smell to us. Foods give off invisible fumes that we breathe into our nasal④ passages. The smelling nerves react immediately to these fumes and we become aware of the smell of these foods.
① terribleadj. 令人讨厌(或不快)的；可怕的，吓人的，可怖的
② savourn. 滋味；气味；风味；【喻】味道；食欲；爱好
③ receptorn. 感觉器官；感受体；受话器；收报机
④ nasaladj. 鼻的；鼻音的
食物的味儿
众所周知，食物都有自己的味儿。有的甜，有的苦，有的很香，有的则难闻。品尝一口食物，我们就会知道它的味道如何；闻一闻，我们同样可以分辨出它是什么样的食物。可是，是什么使我们得以知晓食物的味的呢？是味觉和嗅觉帮了我们的忙。
我们进食时，味觉和嗅觉是同时工作的。我们的舌头上分布着味蕾，里面有神经感受器。它们只对四种不同的滋味作出反应——甜味、酸味、咸味和苦味。其余许许多多的滋味则取决于我们所闻到的食物的气味。食物释放出看不见的气体，被我们吸进鼻腔。嗅觉神经立即对此作出反应，我们便闻出了食物的气味。