【单选题】《中药品种保护条例》规定,中药一级保护品种的保护期限分别为
【单选题】Why did the writer want to send letters to his father?
A.
To express gratitude to him.
B.
To show his father what his life is like
C.
Because he miss his father
D.
To tell him about his recent personal experience
【单选题】《中药品种保护条例》规定药二级保护品种的保护期限是
【单选题】《中药品种保护条例》规定,中药二级保护品种的保护期限是
【单选题】盐酸小檗碱少许,加水5ml,缓缓加热溶解后,加5%氢氧化钠溶液2滴,再加丙酮4滴,即生成( )黄色沉淀 即为丙酮小檗碱。
【单选题】如图所示,∠CDE与∠DEB的关系是 [ ]