请写出下列叙述的正规表达式（regular expression）：
“Each word must start with two digits, followed by a upper case letter, and
then followed by at least one letter either upper case or lower case.”
请问关于这段的表达式，没有相关 关键字 要如何解答呢??
请益一下解答的方向是??

[0-9][0-9][A-Z][a-zA-Z]* 之类的...

\d\d[A-Z][a-zA-Z]+