下列有关实验现象的描述正确的是[ ]
A.红磷燃烧产生白雾
B.硝酸铵溶于水温度升高
C.碘与淀粉作用呈蓝色
D.铁与稀硫酸反应溶液为棕黄色
答案：C
根据句意及汉语提示完成句子。
1. We must obey the traffic _____ (规则).
2.They often go out for a walk by the _____ (小溪).
3. It's too dark outside.I can't see the blackboard _____ (清晰地).
4. Has anyone got any _____ ( 建议) for how to solve the problem?
5. You _____ (一定不能) laugh at the people in trouble.
6. Maybe the little boy is _____ (非常饿的). Pass him a piece of bread.
7. The _____ (绳子) was not strong enough, so we must change it.
内起源
