Question

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

1. A.
   Your having read
2. B.
   While reading
3. C.
   If reading
4. D.
   When you read

Answer 1

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。