When to use "in" and "on" in a sentence

[EmilyAnne]

I always have difficulty with using the words "in" and "on" in a sentence. For example, is it " he's sitting in or on a chair"? He's now in the highway? or on the highway? He's now in Staten Island? or on Staten Island? the kids are on the beach or at the beach? He's lying in bed or on the bed? He's lying on the sofa or in the sofa? He's lying on the couch or in the couch?

Can you give me instances when one should use "in" instead of "on" and vice versa?

Thanks

[anahita]

Dear EmilyAnne,
We use(in ) we have a space, for example when you are sitting on a wooden hard chair you must say (on) a chair but when you have sitting in a soffa you must say (in) a soffa because the surface of a soffa is very smoth and soft.
As well, when you are driving on a high way if you have much speed you must say (over highway) but if you don't have any speed you must say (on a highway) and so on.

[raymon0902]

the kids are on the beach.
He is lying on the bed.
====
in is adjective:

# in the room

# in the Soviet Union

# in the sky

# in the crowd

# in the dark

# in the rain

# in a storm

# to serve in the army
----
# in spring

# in 1945

# in the morning

# the first time in one's life

# in an hour

# it was done in a day
----
In is adverb:

* to walk in

* to lock somebody in


* is anyone in?

* summer is in

* the train is in

* the boat is in

[irshad]

example for in:
My driving licence expire in 2015. or
My exams starts in march.

for on:
He is coming on 14.
My exams starts on friday.