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 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 cannotIdeographs(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（18）