Can we say "by what"? like "by which".
if not,what's the preposition of what?
I've a lot of problems with the prepositions,what should i do?
thanks a lot.
and can we use "by what" in the sentence?
That is not exactly a helpful answer, because one can create situations in which almost any two words in English can appear next to each other.
As Raymott suggested, try putting the words in a sentence in which you think they might be possible, and we'll tell you if you are right.