how to deal with 是等于what to do 还是what to do with
都不一样，应该等于howtodo，意思是怎么做～
Whattodo是做什么，whattodowith是用什么做的意思～
到底是what to deal with 还是how to deal with
看你怎么用。给你举个例子。
Idon'tknowwhattodealwith.
Idon'tknowhowtodealwithit.
dealwith后面要接一个宾语，what可以充当宾语，而how不可以。所以应该是whattodealwith
how to deal with
howtodealwith宾语
而在whattodealwith句式里,what就是dealwith的宾语,所以你不能再加一个宾语了