单项选择题
A.gave B.looked C.sent D.got
A．people cannot sent visible information until 19th century B．we cannot communicate without sound C．the ways of communication are similar in different countries D．in ancient time, enough people is necessary to send messages over distance
A．one’s color preference shows one’s character B．you can brighten your life with wonderful colors C．psychologists have been studying the meaning of color preference D．one’s color preference has something to do with his character and colors have effects on human beings