Please tell him that he can come back ____ _____ _____ _______.请告诉他什么时候想回来就回来.

Please tell him that he can come back ____ _____ _____ _______.请告诉他什么时候想回来就回来.

any time he likes

any time he wants

when he wants to

whenever he wants to 才对
这个to是不能少的，是to come back的省略