下列做法对人体健康不会造成危害的是（ ）
A．面粉中添加增白剂
B．奶粉中添加三聚氰胺
C．食盐中添加适量碘酸钾
D．饮料中添加塑化剂
答案：C
The witnesses ______ by the police just now gave very different descriptions of the fight.
A．questioned
B．being questioned
C．to be questioned
D．having questioned
简述色谱分析进样用注射器的注意事项。
