When I saw them last time,they were working ___ the farm.A at B in C by D on应该选哪个?为什么?

问题描述:

When I saw them last time,they were working ___ the farm.A at B in C by D on
应该选哪个?为什么?

D on
on the farm 在农场 ,固定搭配。

D在农场是固定搭配。

D on
on the farm 在农场 ,固定搭配.

D on
on the farm 在农场