下列材料属于绝缘材料的是（）。
A.橡皮、塑料、陶瓷；
B.水和盐溶液；
C.铜和铝、铁；
D.酸碱溶液。
参考答案：A
用所给单词的适当形式填空
1. If you're tired, why not stop____ (have)a rest?
2. ____ (recycle) books and paper is a good way (protect) the environment.
3. I don't____(agree) with you.I think zoos are terrible places for animals.
4. He is against (put) animals in cages.
5. People should stop____(ride)in cars and start (ride)bikes to help save the planet.
下列哪项不属于矽肺的分期()
A．0期
B．Ⅰ期
C．Ⅱ期
D．Ⅲ期
E．IV期
