Hello, like the other people here I agree that prepositions are hard to learn, so many of them have to be committed to memory. However, there are three basic prepositions for time and for location that are easy to memorize. I would like to share that with you.
Prepositions AT, ON, and IN for location.
We use the preposition AT for a specific address.
ex: I live at 123 Grammar Avenue.
We use the preposition ON for a street or a boulevard.
ex: I live on Grammar Street or... I live on Grammar boulevard.
We use the preposition IN for a general area, city, state or country.
I live in Los Angeles. I live in America.
Prepositions AT, ON, and IN for time.
We use the preposition AT for a specific time.
ex: I'm leaving here at 3:45.
We use the preposition ON for days and dates.
ex: I'll see you on Monday. I'll see you on the 4th of July.
We use the preposition IN for nonspecific times during a day, month, season or year.
I'll see you in the afternoon. I'll see you in August. I'll see you in Winter. I'll see you in 2010.
Do you see how the prepositions have similar usage for both location and time? At is for the most specific thing, and "in" is for the most nonspecific thing.
The difference between IN and INTO.
When we want to say that we placed something somewhere, we have prepositions like IN and INTO.
You should always assume that you will use the preposition IN for the most part. He put me in the timeout area. I am in the room. I am in the building. IN is being used to express that something or someone is inside the area of a place.
However, the times that you will want to use INTO will be when you want to express that something is being *contained*. Instead of being in the area of a place, you are going to say that it is inside the volume of an object.
ex: I poured the milk into the glass.
ex: I put the rice into the bag.
ex: I shoved garlic into the steak to marinate it.
Prepositions FOR and SINCE
When you want to measure time or distance, you will use FOR.
I've been walking for 5 hours. I've been walking for 5 miles.
When you want to show when something had started, you will use SINCE.
I've been walking since 9:00 am.
I've been typing since 8:00 AM.
Preposition OF
This preposition is usually put inside a measurement of something. In English we have certain types of nouns that we call NONCOUNT nouns, and these refer to nouns that can't be counted as individual parts. For example; water, sky, rice, milk and love are considered noncount nouns, because they are considered a whole, as something that cannot be divided. However, when you want to apply a measurement to them, OF is going to be there to help.
ex: Milk... A glass OF milk.
ex: Rice... A bag OF rice.
ex: love... I'm showing her a lot OF love.
Prepositions BETWEEN vs. AMONG.
These prepositions are used to show where someone or something is located.
We say BETWEEN when it comes to just two objects or groups.
ex:He is between the two trees.
ex:I can't decide between the Republicans the Democrats.
We use AMONG for 3 or more things.
ex: He is AMONG the trees. (means more than two trees.)
ex: He is AMONG friends. (means around more than 2 friends.)
Anyways, I hoped this helped, here is a link that I've learned from, and it provides even more information.
http://owl.english.purdue.edu/owl/resource/594/01/