單選題
Some animals that cannot see can still tell the difference between light and darkness, while others can react to chemicals, which is something like smelling and tasting. However, there may be a sense that we know nothing about, for otherwise it is very hard to explain how birds, animals and even insects and fish manage to travel long distances without losing their way.
一些沒有視覺的動物，仍能辨別出光線和黑暗的不同，而其它一些動物能對化學物質做出反應，就如同有味覺和嗅覺一樣。然而，一定存在一種我們不知道的感覺。因為如果不是這樣的話，就很難解釋為什么鳥、動物甚至昆蟲和魚能旅行很長的距離而不迷路。
相關內容： 2013年自考英語每日一練匯總
（責任編輯：中大編輯）
