植物油脂碘值测定中所用到的韦氏试剂是什么？
参考答案：韦氏试剂是指含一氯化碘的乙酸溶液。
He told me he had finished the work ______.
A．two days ago
B．the day before
C．the next day
D．the day before yesterday
同位素试剂是非密封型放射源。
