Human beings act in a different way from that of animals just because they can speak while animals cannot. Even the cleverest animals cannot do things which to us seem very 【B1】 and which small children, as soon as they learn to 【B2】 , would be able to do.
A German scientist, who made 【B3】 for many years with big apes, found that his apes could use sticks as 【B4】 to pull down bananas which they could not 【B5】 . But they 【B6】 used the stick to get the banana when both the stick and the banana were in 【B7】 at the same time. 【B8】 the banana was in front of them and the stick was 【B9】 them, they could 【B10】 use the stick. They could not bear the 【B11】 in mind long enough to look 【B12】 and pick up the stick and then use it. The 【B13】 for this is clear. 【B14】 have words for banana and stick which 【B15】 us to think about these when they are not in 【B16】 . Even a small child knowing the words "banana" and "stick" has an 【B17】 of their relationship and is able to think of "stick" together with "banana" and to 【B18】 this long enough to pick the stick from behind and use it on the banana. Unable to speak, animals cannot 【B19】 their knowledge of things for long. That is 【B20】 they often interrupt one line of action to do something else and later forget it completely. Human beings, on the other hand, use language and are able to go after one thing continuously and do it with a clear aim.