Writing is a system of humancommunication by means of visual sy

Writing is a system of humancommunication by means of visual symbols or signs. The earliest stages ofwriting  16  almost from the dawn of humanity.

Counting devices have been used in allparts of the world. Such devices  17  sticks,pebbles, claytokens, and strings. For example, a shepherd could record the  18 number of sheep in his flock by cutting one notch(刻痕) in a stick for eachsheep. He could also keep pebbles of about the same  19  orshape in order to represent the different kinds of animals in his 20  .

Rock drawings conveyed a clearer meaning,but were not so useful for counting.A simple rock drawing shows a mountain goatand a man  21  a horse. The mountain goat stands on all fours,but the horse and rider are upside down. The design  22  ahorseman that a mountain goat can climb the  23  trail, butthat his horse cannot

Ideographs(象形文字) express an idea  24  anyclear connection with any language.For example, a picture of a smiling facerepresents happiness. Any person can understand the idea of such a drawing, nomatter  25  he or she speaks the language of the person who drewit. This way of expressing ideas, not necessarily  26  , iscalled ideography. Pictures drawn for ideas differ only slightly from picturesdrawn for artistic  27  .Communication pictures are simplifiedand stereotyped, and they have no  28  that are not needed aspart of the communication.

Human beings took the decisive 29  in developing real writing when they learned to express ideasindirectly. They did this by using  30  that stood for thewords in their language, not the ideas the words stood for. This kind ofwriting is called logography.

 
请选择恰当选项填入（21）

A.feeding

B.riding

C.training

D.leading

正确答案是B