判若两人

Jack Ma was pretty mediocre in his childhood, but he turned out to be as wise as Solomon and  a real ball of fire while embarking on E-commerce.

马云童年时表现平平，但一旦搞起电子商务，他精明能干，聪明过人，活力四射，完全判若两人。

Notes:

1) mediocre [,midɪ'okɚ]: not very good 一般的，平凡的，平庸的

I thought the book was pretty mediocre. 我认为这本书非常一般。

a mediocre student 能力一般的学生

2)as wise as Solomon:极有智慧; 像所罗门一样聪明;非常聪慧

3)a ball of fire:一团火；〔美国〕精力奋发的学生[实干家]；〔美俚〕特别快车;精力充沛的人；一个非常活跃的人；活跃的人

4)embark on: 开始(工作)；着手，从事:

He has already embarked on his new dictionary.

他已开始编他的新词典。

to embark on a business career开始经商