【简答题】食盐按加工精度分为粗盐、精盐、 __________ 等。
【单选题】I reached home it began to rain. A. No sooner, than B. No sooner, when C. No sooner had, than D. No sooner had, when
【判断题】I had no sooner reached home than it began to rain. 改写成倒装句为: No sooner have I reached home than it began to rain.
【单选题】设f(x)为可导函数,且满足条件 lim x→0 f(x+1)-f(1) 2x =3 ,则曲线y=f(x)在点(1,f(1))处的切线的斜率为( )
【简答题】I had no sooner entered home than the bell rang. (No sooner...)
【简答题】(15分)【化学与技术】 氯碱工业中曾用石棉隔膜电解槽来电解食盐水,下图即为石棉隔膜电解槽的示意图,回答下列问题: (1)产物A是 ;产物B是 ;产物C (2)石棉隔膜能阻止 不能通过,但不能阻止 通过。 (3)粗盐水含Ca 2 + 、Mg 2 + 、SO 4 2 - 等杂质离子,这些离子的存在除了会影响电解所得产品的纯度外,主要会 所以电解食盐水要求对粗盐水进行精制,请将精制时除去上述三种离子通...