第3个回答 2013-08-07
How about: He is in his farm. He is on his farm. He is at his farm. All these sentences are grammatically correct in every way. But each has slightly different meaning.
These three prepositions: in, on and at are all very similar. It is difficult to use them correctly at every time even for most people with English as mother tongue. I shall attempt to explain it.
He is in his farm - using 'in' denotes he is physically inside the boundary of his farm. 'In' in this sentence is similar to 'within'.
He is at his farm - 'at' in this sentence imply he is either inside the boundary of his farm or near it. The speaker is not very sure his exact location, but speaker know he is somewhere near his farm. However, if the speaker is physically inside the boundary of this farm, then the speaker cannot say this sentence. The speaker has to say either he is on the farm or in the farm.
He is on his farm - denotes he is physically inside the farm. But, the farm becomes a physical object equals to land. You cannot be in 'land', you can only on 'land', So, the 'farm' equals to land. While if using 'in', farm equals to 'farm' as a descriptive term for the function of this land, not just a piece of land.
OK. You want to know which one you should use. This depends upon what are you writing.
Note: I have skip all the special fixed use of these prepositions. I just talked about these 3 sentences.
Questions? Am I making you all more confused?