A．Dogs chosen for guiding the blind must be intelligent and patient. B．Some kinds of dogs are born to be guide dogs. C．At the age of two guide dogs begin a five-month intensive course. D．Most blind people could find the guide dogs helpful.
A.Dogs B. B．Some C. C．At D. D．Most E.
【参考答案】
A 解析：选项中重复出现的guide dogs以及其中的chosen，intensive course等表明，本......