【单选题】抗组胺药盐酸苯海拉明的化学结构属于下列哪种类型
【单选题】People usually say '_____' before going to bed. [ ]
【单选题】Drivers usually have _____ good sense of direction.
【单选题】抗组胺药盐酸苯海拉明的化学结构属于下列哪一类
【单选题】Usually, good desks are made ______ good wood. [ ]
【单选题】在萃取时,可利用( ),即在水溶液中先加入一定量的电解质(如氯化钠),以降低有机物在水中的溶解度,从而提高萃取效果。