（2）表示地点的介词
1）at, in, on
at一般指小地方；in一般指大地方或某个范围之内；on往往表示“在某个物体的表面”。例如：
He arrived in Shanghai yesterday.
They arrived at a small village before dark.
There is a big hole in the wall.
The teacher put up a picture on the wall.
2）over, above, on
over, on和above都可表示“在……上面”，但具体含义不同。Over表示位置高于某物，在某物的正上方，其反义词是under。 above也表示位置高于某物，但不一定在正上方，其反义词是below。On指两个物体表面接触，一个在另一的上面。例如：
There is a bridge over the river.
We flew above the clouds.
They put some flowers on the teacher’s desk.
3）across, through
across和through均可表示“从这一边到另一边”，但用法不同。Across的含义与on有关，表示动作在某一物体的表面进行。Through的含义与in有关，表示动作是在三维空间进行。例如：
The dog ran across the grass.
The boy swam across the river.
They walked through the forest.
I pushed through the crowds.
4) in front of, in the front of
in front of 表示“在某人或某物的前面”，在某个范围以外；in the front of 表示“在……的前部”，在某个范围以内。例如：
There are some tall trees in front of the building.
The teacher is sitting in the front of the classroom.