精确到0.01mg指的是误差范围为0.01mg,即称取的原料应该为9.99到10.01之间.
既然说了是精确称取,那就不是about了,要用exactly这类的词来纯强调准确性.

支持这种说法，不能再about了。

粗略称量：
Weigh approximately 0.1 g of potassium chloride and place in a beaker.



精确的说法：
Place exactly 0.1646 g of sodium chloride in a 1-l volumetric flask.

Weigh the cylinder to the nearest 0.1 g and mount it as shown in Fig. 4.

Weigh the beaker and residue to the nearest 0.1 mg.
Weigh approximately 45 g of potassium hydroxide pellets into a 100-mL volumetric flask.
Weigh 1.571 g ± 0.1 mg CuSO4 5H2O and transfer to a 1000-mL volumetric flask.
Weigh out 17 gms of silver nitrate and transfer to a 2 litre beaker.

Accurately weigh a clean dry stoppered 250 ml conical flask W1.
Accurately weigh a clean oven-dried porosity four sintered glass crucible W1.
Accurately weigh a clean oven-dried porosity four sintered glass crucible – weight ‘W1’.
Dissolve 1.9069 g KCl (element fraction K = 0.5244) dried at 110¡ãC, weighed accurately to at least four significant figures, in water, and dilute to volume in a 1,000 mL volumetric flask with water.

谢谢你的意见！我在3楼的帖子中是这么说的：“精确称取（/精密称定）样品约10mg：accurately weigh （/weigh accurately） about 10 mg of the sample.这样表达从语法上严格来说是不对的，但现在大家都已经习惯了这样写，包括药典上也是这么写的。”我又看了一下药典，发现这句话说得不够准确。中国药典上习惯用accurately weigh （/weigh accurately） about * mg，美国药典则很少有这样的用法。USP的常见用法如：

Transfer about 100 mg of *, accurately weighed, to a 20-mL volumetric flask.

Dissolve an accurately weighed quantity of * in chloroform to obtain a solution having a known concentration of about * mg per ml.

精确到0.01mg，只是对天平精度的要求，不是称取的原料应该为9.99到10.01之间.

而且，按国药典理解，取样品约10mg（精密称定），这种说法也是对，因为药典凡列有说：“精密称定”系指称取重量应准确至所取重量的千分之一；

不知我理解有错没，望指教！