答案：B

题目分析：考查特殊句型。本题是由特殊句式：祈使句+连词+陈述句，转换而来。祈使句+连词+陈述句=If引导的条件句+主句。这个句型进一步转换成：名词短语+连词+陈述句。本题One talk with the student, and you will find the boy is very outgoing．="If" you have a talk with the student, you will find the boy is very outgoing.句意：如果你和这个学生谈一会，你就会发现他非常外向。A项是现在分词做状语用法，D项是条件状语从句，如果去掉第二句开头的and，那么AD都是正确的。C项是过去分词做状语，与后面句子主语没有任何的联系，故不能选。综合以上分析，本题B正确。

点评：本题是由特殊句式：祈使句+连词+陈述句，转换而来。祈使句+连词+陈述句=If引导的条件句+主句。这个句型进一步转换成：名词短语+连词+陈述句。本题One talk with the student, and you will find the boy is very outgoing．="If" you have a talk with the student, you will find the boy is very outgoing.