问题详情：
______ the medicine works in human body is a question ______ not everyone can fully understand.
A．How; that B．That; which C．What; which D．How; what
【回答】
A
【详解】
考查名词*从句和定语从句。句意：*物怎么在人体中起作用不是每个人都完全能理解的问题。分析句子可知， ______medicine works in a human body在句中做主语，空白处表“怎样”，所以填how；______not everyone can understand fully是定语从句，先行词是question，是物，在从句中做understand的宾语，所以从句的连接词用thatwhich。故选A。
知识点：定语从句
题型：选择题
