Thanks,
Does this rule always work?
For example,
(1) Please wait for me at/in the shopping centre.
"in" means inside the building.
"at" may mean inside the building or immediately outside it.
(2) Please wait for me at the entrance of the university.
"in" is wrong.
(3) There is a car in/at the farm.
"in" means inside the farm.
"at" may mean inside the farm or immediately outside it.
(4) There is a special plant in/at this mountain.
"in" means inside the farm.
"at" may mean inside the farm or immediately outside it.
How about "on"?
Could anybody please correct my ideas and understanding to all these posts.
Many thanks in advance