题目

 “=”是“”的 (     ) A．充分不必要条件                     B．必要不充分条件  C．充要条件                           D．既不充分也不必要条件 答案：A   “=” “ “=”，反例：听下面一段材料，回答第1-3题。 1. Who are these two speakers? [     ]A. Students. B. Teacher and student. C. Business partners. 2. Why, according to the man, do many American families have two phone lines? [     ]A. The children enjoy talking on the phone. B. Family members all need to use the phone. C. American families have a lot of business needs. 3. What can we learn about the woman? [     ]A. She agrees that telephones discourage reading and writing. B. She thinks telephones have both advantages and disadvantages. C. She has a positive attitude toward telephone.