单项选择题
A. a one B. the one C. the ones D. these ones
A. how individuals can help make a difference B. running a neighborhood meeting to solve its problems C. citizens’reactions to the problems they face D. solving problems through group action
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