通常情况下，下列各组物质中，都属于绝缘体的是（ ）
A．空气、塑料、人体
B．陶瓷、湿木材、橡胶
C．空气、油、塑料
D．玻璃、油、大地
A、空气和塑料是绝缘体，人是导体．故A不符合题意．
B、陶瓷和橡胶是绝缘体，湿木材是导体．故B不符合题意．
C、空气、塑料和油都是绝缘体．故C符合题意．
D、玻璃和油是绝缘体，大地是导体．故D不符合题意．
故选C．
| 根据对话内容，从方框内的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。 | |
B: Hello! Mike. This is Tom speaking. A: Hi, Tom. B: 2_______ A: Tomorrow is Sunday. Yes, I am free. 3_______ B: Jim, Jack, Linda and I want to have a picnic. 4_______ A: I'd love to. What can I bring? B: Well, you can bring your guitar and kite. A: Sure, I won't forget them. 5_______ I think he would like to go, too. B: All right. Please ask him to bring some water. A.OK, thanks, Tom. |