在CO、C、H2、CO2四种物质中，哪种物质具有不同于其他三种物质的特点（写出两种情况，说明原因）．（1）______；（2）______．
一氧化碳、氢气、碳具有可燃性和还原性；碳是固体，一氧化碳、二氧化碳、氢气是气体；另外还可以看组成，一氧化碳、碳、二氧化碳都含有碳元素，而氢气不含．此处不限定与性质，可以是性质，可以是用途还可以是组成．故答案为：C 是固体；CO2 没有还原性．（其他合理也可）
| 补全对话.阅读下面对话,从方框内7个选项中选择5个恰当的句子完成此对话, 并将其番号填入题前括号内。 | |
B: They are talking about yesterday's football match. A: Oh, I watched it on TV. Beijing Team had a good teamwork. Didn't you watch it? ( ) B: 2 I did my homework and forgot the time. So I missed the match. ( ) A: 3 But Beijing Team will play again this evening. ( ) B: 4 ( )A: Sure. You'd better finish your homework earlier if you want to watch it. Remember: 5 |