A language is a signaling system which operates with symbolic vocal sounds (语声), and which is used by a group of people for the purpose of communication.

　　Let’s look at this __1__ in more detail because it is language, more than anything else, __2__ distinguishes man from the rest of the __3__ world.

　　Other animals, it is true, communicate with one another by __4__ of cries: for example, many birds utter __5__ calls at the approach of danger; monkeys utter __6__ cries, such as expressions of anger, fear and pleasure. __7__ these various means of communication differ in important ways __8__ human language. For instance, animals’ cries do not __9__ thoughts and feelings clearly. This means, basically, that they lack structure. They lack the kind of structure that __10__ us to divide a human utterance into __11__.

　　We can change an utterance by __12__ one word in it with __13__: a good illustration of this is a soldier who can say, e.g., “tanks approaching from the north“, __14__ who can change one word and say aircraft approaching from the north” or “tanks approaching from the west”; but a bird has a single alarm cry, __15__ means “danger!”

　　This is why the number of __16__ that an animal can make is very limited: the great tit (山雀) is a case __17__ point; it has about twenty different calls, __18__ in human language the number of possible utterances is __19__. It also explains why animal cries are very __20__ in meaning.

　　1.A) classification B) definition C) function D) perception

　　2.A) that B) it C) as D) what

　　3.A) native B) human C) physical D) animal

　　4.A) ways B) means C) methods D) approaches

　　5.A) mating B) exciting C) warning D) boring

　　6.A) identical B) similar C) different D) unfamiliar

　　7.A) But B) Therefore C) Afterwards D) Furthermore

　　8.A) about B) with C) from D) in

　　9.A) infer B) explain C) interpret D) express

　　10.A) encourages B) enables C) enforces D) ensures

　　11.A) speeches B) sounds C) words D) voices

　　12.A) replacing B) spelling C) pronouncing D) saying

　　13.A) ours B) theirs C) another D) others

　　14.A) so B) and C) but D) or

　　15.A) this B) that C) which D) it

　　16.A) signs B) gestures C) signals D) marks

　　17.A) in B) at C) of D) for

　　18.A) whereas B) since C) anyhow D) somehow

　　19.A) boundless B) changeable C) limitless D) ceaseless

　　20.A) ordinary B) alike C) common D) general