What time do you start school?
Which lesson shall I start with?
(1)为什么start接school不需要加介词,而lesson就需要加介词?
He started on cleaning the room.
He started in business.
we'll start in on discussing chemical equilibrium
(2) 而加介词时,一会用on、一会用in、一会又是in + on 。。。这,老师能讲讲这些个搭配都有什么区别啊?