▲閱讀下文，回答第 46-50 題
        Quite a few pet owners say that they are able to communicate with their beloved animals bylooking at their body language signals. This claim is not surprising to animal scientists due to thefact that they have discovered that animals can communicate not just between themselves butwith humans as well.
        Here are some interesting findings on the secret languages of animals. It’s commonly knownthat a dog usually wags its tail to show its happiness and excitement. But do you know that whena dog’s tail moves more to the left, it implies negative feelings like anger and disappointment?Another amazing finding is that the average dog can understand about 160 words in total andtherefore can physically respond to their owners’ directions. Interestingly, cats use their eyes tocommunicate. They blink slowly when they feel totally comfortable with the people around them.Rabbits like to grind their teeth to show they are enjoying themselves and feel comfortable. Somepet birds rapidly enlarge or shrink the pupils in their eyes to help their owners to get an accurateemotional reading. In the world of hamsters, yawning does not convey a message of being tired.Hamsters actually yawn to indicate that they are feeling quite content and peaceful at the moment.
       Do you have trouble communicating with your pets? Instead of shaking your head infrustration because you do not know what your pets want to express, try to understand the truemeaning behind their behaviors.
【題組】46. What is the main idea of the passage?
(A) The judgment of animal instinct.
(B) The consistence of animal behavior.
(C) The discovery of animal intelligence.
(D) The recognition of animal communication.