________ the poem a second time, the meaning will become clearer to you．

A.Your having read

B.While reading

C.If reading

D.When you read

答案及解析： D

解析：

选项A是动名词，与后面的成分存在语法错误；

选项B、C的逻辑主语应该是人，但此句的逻辑主语是the meaning。D项为最佳答案。