题目

制作人体口腔上皮细胞的临时装片时，在载玻片上滴一滴（ ） A . 清水 B . 稀碘液 C . 生理盐水 D . 自来水 答案：C It is difficult to judge whether what he did ________.        A．is worth to be praised                   B．deserves being praised        C．is worthy of being praised                D．is worth being praised