英语翻译For about twenty years scientists have tried to teach ch

英语翻译
For about twenty years scientists have tried to teach chimps (黑猩猩) to talk like people.But they have failed.
Chimps hear well.Different words do sound different to them.But chimps don't have a speech center in the brain for speaking as people do.So other ways have been found to teach chimps how to speak.
Plastic pieces of different forms and color were used to teach Sarah the chimp.Each piece stood for one word.Sarah's teachers "wrote" by putting the pieces on a board.Sarah read these messages.Then she "wrote" her answers back.Later Sarah learned more different messages.And she learned to follow directions in the messages.