Troublesome Words
Lie, Lying, Lay, Lain vs. Lie, Lying, Lied, Lied
"Lie" is an intransitive verb meaning "to rest" or "to be at rest." Its forms are: lie, lying, lay, lain.

EXAMPLE
Lie down.
Lying in the sun dries our skin.
The parcels lay on the table.
We have lain in the sun for thirty minutes.

"Lie" can also mean make an untrue statement. It is an intransitive verb whose forms are: 'lie' and lying (present), 'lied' (both past and participle.)

EXAMPLE
Please don't lie to me.
He was punished for lying.
They lied to their parents.
They have lied before.

Lie, Lying, Lay, Lain vs. Lay, Laying, Laid, Laid
As you learned in the last lesson, "lie" means to be at rest or to recline in a horizontal position. Its forms are: lie (present), lying (present/past progressive), lay (past), lain (participle).

EXAMPLE
Lie down.
Lying in the sun dries the skin.
The parcels lay on the table.
We have lain in the sun for thirty minutes.

Unlike "lie," "lay" is a transitive verb, so it always takes an object. Remember that "lie" never takes an object because it is intransitive. The forms of "lay" are lay, laying, laid, laid.

EXAMPLE
Lay the bricks here.
He was laying the bricks in rows.
Yesterday he laid the bricks ten high.
He has laid all the bricks in the wall.

"It's" is a contraction meaning "it is."

EXAMPLE
Its appearance was misleading.

Tips:
Note that the present tense of "lay" is the same as the past tense of "lie."

Its vs. It's, 'Tis
"Its" is the possessive of the pronoun "it." Note that there is no apostrophe. "It's" is a contraction meaning "it is."

EXAMPLE
It's a long way to Tipperary.

"It's" can also be a contraction meaning "it has."

EXAMPLE
It’s been 10 years since I saw her.

"'Tis'" is also a contraction meaning "it is."

EXAMPLE
'Tis seldom used in modern English.

Set vs Sit
"Set" is, in most ordinary uses, a transitive verb needing an object. It means to put or place something in a certain position, or to arrange. Its principal parts are: set, setting, set, set.

EXAMPLE
She set the table.
He set the watch.

"Sit" is, in ordinary usage, an intransitive verb. It means to rest somewhere (like a chair) in an upright position. Its principal parts are: sit, sitting, sat, sat.

EXAMPLE
He sits down.

"Sit" can also be used to talk about where an object is located.

EXAMPLE
The clock sits on the shelf.

In a few instances "sit" is used as a transitive verb, such as in:

EXAMPLE
He sat himself down.

Your vs. You’re
You have probably encountered confusion between your and you're in many Internet posts. Sometimes people write comments like "your so pretty in this picture" when they really mean "you're so pretty in this picture."

So what's the difference? Just remember—you're (with the apostrophe) is a contraction meaning you are, but your (no apostrophe) indicates possession or ownership. Let's look at our first example in more detail:

You can see that whoever posted this comment should have used you're (you are), not your(possessive).

Hint:
If you can replace the word with you are, use the apostrophe.

EXAMPLE
You're the best! ⇒ You are the best!

Now let's look at a few examples of the possessive your:

In this example, the person you are talking to owns the dog.

EXAMPLE
Your dog is very friendly.

The positive attitude "belongs" to the person, even though it's not something he or she actually owns.

EXAMPLE
We admire your positive attitude.

Their, There and They’re
"Their" is the possessive form for the plural pronoun "they."

EXAMPLE
They used their money on video games.

The word "there" has several meanings. As an adverb it means in, at, or about that place.

EXAMPLE
Place the book there.

When used as a noun, "there" means that place.

EXAMPLE
Are you from there, too?

When used as an interjection, "there" expresses an exclamation of triumph or relief.

EXAMPLE
There! It is finished.

"They're" is a contraction meaning "they are."

EXAMPLE
They're going to the show.

Who vs Whom
Some people think the main difference between who and whom is the way they sound, with whom being the more formal way to say who. In reality, the distinction between them is grammatical.

Even though who and whom are both pronouns, they do completely different jobs in a sentence—who acts as the subject while whom acts as the object.

Just remember to use who to refer to the person who is propelling the action in a sentence; use whom when the person is having the action done to them. You also use whom, never who, as the object of a preposition.

Who	Whom1
Subject pronoun	Direct or indirect object pronoun
Never use as the object of a preposition	Must use with prepositions

Let's look at some examples:

EXAMPLE
Students who study hard usually earn excellent grades.

The pronoun, who, is referring back to the subject, students. (Who earns excellent grades? The studentsdo.)

Because the pronoun is referring to a subject, it would be incorrect to use the object pronoun whom.

EXAMPLE
Earning excellent grades also depends on whom you study with.

This sentence has two clauses, but for the purposes of this lesson we'll focus only on the second one, whom you study with.

In this clause, whom is the object of the preposition with, so it would be incorrect to use the subject pronoun who.