"他已经习惯于做某事"还是用he is used to doing 吗?

used to do sth
习惯做某事

这是固定搭配，记住就好～～

因为是已经，所以用完成时
用has been used to doing

be used to do 是指过去常常做某事
has been doing 是过去完成时
好象都没有楼主说的意思

是的
be used to doing sth 习惯于
used to doing sht 常常

has been used to doing

he is used to doing