将钠、镁、铝各0.3 mol分别放入100 mL 1 mol·L-1的盐酸中,同温同压下产生的气体体积比是( ) A.1∶2∶3 B.3∶1∶1 C.6∶3∶2 D
温室栽培胡萝卜,采用什么颜色的玻璃做顶棚更能提高产量 A.红色玻璃 B.蓝紫色玻璃 C.绿色玻璃 D.无色玻璃
下面的烷烃是烯烃R和氢气发生加成反应后的产物,则R可能的结构简式有A、4种 B、5种 C、6种 D、7种
Americans think that travel is good for you, some even think it can help one of the country's worst problems-crime (犯罪). Crime worries a lot of people. Every year, the number of crimes go
When I was 17, I read a quote: “If you live each day as if it were your last, someday you’ll most certainly be right.” It made a(n) 36 on me,and since then,for the past 33 years, I h
学古诗,发幽思,在西子湖畔“ ,谁家新燕啄春泥”令我充满活力;在北固山下,“海日生残夜, 。”令
请将下列传染病连到对应传播途径上呼吸道传染病 A 沙眼消化道传染病 B 非典