A:只须验证它完全燃烧后产物只有H2O和CO2
B:只须测定其燃烧产物中H2O和CO2物质的量的比值
C:测定完全燃烧时消耗有机物与生成的CO2、H2O的物质的量之比
D:测定该试样的质量及试样完全燃烧后生成CO2和H2O的质量
Our classroom is very clean because we every day.
She used to in the morning,but now she is used to at night.
作者写教阅水军与吴中健儿在潮头弄潮,既写风景,又写民俗,人借水势,水借人势,人助水势,水助人势,这样描写有什么好处?