【单选题】In the modern version of the fable, what do the ants do to the grasshoppers?
A.
The ants refuse to provide food for grasshoppers.
B.
The ants lend the grasshoppers the money to buy their goods.
C.
The ants borrow the grasshoppers the money to buy their goods.
D.
The ants persuade the grasshoppers to work for their life.
【简答题】重量法测定钢中钨,称取试样1.0000g得到WO 3 沉淀0.2210g,计算钢中钨的质量分数。
【单选题】沥青 稳定碎石混合料,按图纸所示或监理工程师指示的平均铺筑面积,经监理工程师验收合格的平均面积,按不同厚度以平方米计量。除监理工程师另有指示外,超过图纸所规定的面积均 ( ) 。
【单选题】What is the role of pheromones ill the mass migrations of ants?
A.
Pheromones are used to create a trail that directs the ants during migrations.
B.
Pheromones signal the ants that the nest has been invaded and must be abandoned.
C.
Pheromones control the speed at which ants move from one location to another.
D.
Pheromones enable scouts to identify suitable areas for establishing a new nest.
【判断题】两位分析者同时测定某一试样中硫的质量分数,称取试样均为3.5g,分别报告结果如下:甲:0.042%,0.041%;乙:0.04099%,0.04201%。甲的报告是合理的。
【单选题】测定试样CaCO3 的质量分数,称取试样 ,滴定耗去 EDTA 标准溶液22.60mL,以下结果表示正确的是( )
【单选题】测定试样中MgO的质量百分数,称取试样0.8080g,滴定时消耗了EDTA标准溶液20.50mL,正确的测定结果是( )。