by是甚麼意思？有何作用？刪去by又得嗎？

"by" is a preposition, used for showing how or in what way something is done. (by means of)

"begin by cleaning the floors, and then ..." means the first thing to do is to clean the floors and the next thing is to do the windows.

If you want to remain this meaning, you cannot delete the preposition "by".

by的意思 : 由通過以靠將截至截靠近
用來連接兩句句子
不能