It is a long time since he moved here ,he must have---here.A

答案是A
翻译：他搬来好久了,所以他肯定习惯在这里工作了
语法：
1 used to do sth.-----she used to live here 她以前住在这里
2 be used to do sth----this house is used to store things 这房子被用来存放东西.
be
3 become used to (doing) sth.-------John isn't used to eating with Chinese chopsticks
get (John不习惯用筷子吃饭.)