Common errors in the use of prepositions

Though the prepositions are small words, they are very important ones, and their correct usage is a test of your mastery of the language. This article explains the correct usage of some prepositions that often cause confusion.

Beside and besides

Students often get confused about the meaning and usage of these two words. Beside means 'by the side of' and besides means 'in addition to'.

The house was beside the river. (= by the side of the river)
He stood beside me. (= by my side)
He plays tennis besides (in addition to) basketball and football.
Besides (in addition to) being a good speaker, he is also an excellent actor.

Since and for

This is another set of prepositions often confused by foreign students. Since refers to the starting point of an action. It means 'from a particular point of time in the past' and it should be used with the present perfect tense of the verb.

He has been absent since last Monday. (NOT He is absent since last Monday.)
It has been raining continuously since yesterday morning. (NOT It is raining since yesterday morning.)

For is used to talk about duration. It refers to a period of time.

I have been waiting here for two hours.
We have been living here for three years.

A common mistake is to use since when referring to a period of time. You must not say 'He has been absent since two days' or 'I have been studying since two hours.'

Between and among

We use between to say that somebody or something is between two or more clearly separate objects.

You have to choose between these two options.
I stood between John and Peter.
They marched up the aisle between the pillars.
He shared his money between his wife, his daughter and his son.

Among is used with more than two people or things.

The British were able to conquer India because the Indian princes quarreled among themselves.
The United Nations tries to maintain peace among the nations of the world.

By and with

By is used to refer to the doer of an action; with is used to refer to the instrument with which the action is done.

He was killed by his servant.
He was killed with an axe.
The tiger was shot by me with my new gun.

In and At

In is generally used to refer to large places - countries, districts, large cities etc. At is generally used to refer to small and unimportant places like villages, small towns etc.

We shall meet them at the club this evening.
My brother lives at Mumbai.

This rule is not very rigidly followed now, and in is often used for small places too, though at is seldom used for big places.

On, in, at and by

While speaking about time at indicates an exact point of time, on a more general point of time and in a period of time.

I shall be there at 4 pm.
We set out at dawn.
I was born on May 26.
The postman brought this letter in the morning.
I shall visit them in summer.
It is very hot in the day and quite cold at night.

Note that 'at night' is an exception to this rule.

By is used to show the latest time at which an action will be finished. So it is usually used with the future tenses.

I shall be leaving by 6 o' clock.
I hope to finish the work by the end of this year.

On and upon

On is generally used to talk about things at rest and upon to talk about things in motion.

He sat on a chair.
He jumped upon his horse.

However, this rule is not rigidly followed now, and on is often used to talk about things in motion too.

In and within (time)

In means at the end of a certain period; within means before the end of a certain period.

The spacecraft will reach the moon in three days. (= at the end of three days)
The spacecraft will reach the moon within three days. (= before the end of three days)
The loan should be repaid in a year.
The loan should be repaid within a year.

Note that this distinction too is not always kept and in is often used for within.