—Tom, you'd better go to work by underground. The t_1is very heavy today because of the rain.—Thank

题干

—Tom, you'd better go to work by underground. The t____ is very heavy today because of the rain.

—Thank you, Jane.I will.

上一题下一题 0.0难度选择题更新时间:2016-04-12 12:13:22

traffic

A、对现象的认识	B、对安全的认识
①气体压缩，气体分子之间的间隔变小 ②活性炭除去异味，活性炭具有吸附性 ③电解水时正极与负极产生的气体质量比为1:2	①点燃可燃性气体前一定要验纯 ②煤矿矿井要保持通风、严禁烟火 ③家中天然气泄漏赶紧打开排风扇
C、对鉴别除杂方法的认识	D、对人物贡献的认识
①区分硬水和软水，加肥皂水后搅拌 ②除去CO₂中少量CO，通入足量灼热的氧化铜 ③除去CaO中CaCO₃，高温充分煅烧	①拉瓦锡--测定空气组成 ②门捷列夫--元素周期表 ③张青莲--测定水的组成