Your – You’re

• Your refers to a person’s attributes e.g.
• You’re – short for You are

e.g.

You should try to improve your grammar.

You’re never going to believe this, but, you placed the apostrophe in the wrong place – again!

The simple step is to make sure you’re able to say you are.

For example, it is wrong to say:

You should try to improve you’re (you are) grammar

There Their There

• There refers to a place
• Their refers to a person.

I shall go over there to read the book.
They should remember their grammar and punctuation when writing an essay.

I would like to go there.

Their main problem in travelling to New York was getting over there.

It Its  It’s

• It’s is short for it is.

It’s (it is) a beautiful day.
It’s (it is) a shame I never know the difference between a split infinitive and conjugation.

• Its refers to an object

The main use of a comma is in its ability to separate a sentence into different sections.
(note here we couldn’t say “in it is ability”)

It’s a shame to discard the benefit of its undoubted ability to save time.

“The indefinite “one” is another source of trouble and is frequently the cause of disagreeable scenes. Such a sentence as “One loves one’s friends” is considered by some persons to be stilted and over-formalized, and such persons insist that “One loves his friends” is permissible. It is not permissible, however, because “one” is indefinite and “his” is definite and the combination is rhetorically impossible. This is known as hendiadys and was a common thing in Latin. Rare examples of it still exist and are extremely valuable as antiques, although it is usually unsafe to sit or lie down on one.”

You can find more extended excerpts here:

• Who and Whom

When to Use a Comma.

1. Linking main clauses.

Keynes was an economist. Keynes was intelligent. Keynes was born in England

Each of these 3 sentences is grammatically correct, however, it makes for stilted reading. We can combine these 3 clauses into one sentence.

• Keynes was an intelligent economist, who was born in England.

2. After an introductory element of a sentence.

Monetarism is the study of Money supply. We could add an introductory sentence to this.

• Popularised by Milton Friedman, Monetarism is the study of Money Supply.

These introductory phrases are often known as prepositional phrases; it literally means, “to go before”.

• One more example: In many different countries, economists often fail to predict recessions.

3. Adding a subordinate clause at the end of a sentence.

A subordinate clause is a phrase that couldn’t make a sentence on it its own.

• Economists are very bad at predicting the future, although occasionally they get it right.

The first phrase is a sentence on its own, the last phrase adds to the initial statement, and so is a subordinate clause.

4. Parenthetical Elements in a sentence.

These involve words like “however”, “in fact”, “of course”, and “for example”. These words help to link a sentence together; they need a comma before and after.

• Economics is termed the dismal science, however, occasionally it can be fun to study Economics.

A common mistake, however, is to only include one comma after the “however,” and not before.

• The latest inflation news was disappointing, in fact, the Bank of England was very concerned.

5. Appositive.

This is a term used to rename a noun.

• John Maynard Keynes, Britain’s most famous economist, died in 1946.
• Economics, the study of scarcity, is growing in popularity.

6. Link Between lists.

• The benefits of studying economics include: higher pay, understanding of life, and boundless joy.

7. Comma before quotation

• Milton Friedman repeatedly said, “to control inflation, you must control the money supply”

Sometimes you can use a semi colon, or even colon, before a quote.
8. Surrounding the name or title of a person

• Will you, Tom, do that essay?
• No, Richard, I have better things to do.

9. Use comma to separate statement from question.

• Monetarism is rubbish, do you agree?

10. Use a comma for sentences beginning with yes, well, or now.

• Well, it would be unusual to pass Economics without studying.

11. Use a comma between two adjectives when the word and could be put between them.

• Keynes was an intelligent, innovative economist.

12. Use a comma between independent clauses.

• Keynes was a member of the Bloomsbury set, and he studied hard to become a great economist.

Note: Each phrase could stand alone as a sentence.

Related Links

• When to Use a Comma.
• When to use a comma before “And”
• The Oxford Comma

• 40 Rules for Gooder English - humorous look at Grammar
• Essay Writing Advice at Economics Help