题目

Where is John’s father?A. At work B. At home. C. At schoo1. 答案：【答案】A【解析】W: Have you finished your homework, John? It’s time for supper.M: I'm coining, Mum, but where is Dad? Is he late again from work?W: Yes.此题为听力题，解析略。“三大合成材料”指的是     、    、    ．有机合成材料的出现是对     的一种补充，    在有机合成材料的发展中起着重要作用．