From VOA Learning English, this is Everyday Grammar.

This week, we continue explaining commonly confused words in the English language.

Ashley: That reminds me...Adam, do you still have my grammar book that I let you borrow last week?

Adam: No, I lied the book down on your desk yesterday.

Ashley: You mean, you laid the book on my desk yesterday.

Adam: Lie, lay, laid, lied...what's the difference?

Ashley: That's a hard question to answer. Both words have several definitions. But an easy way to remember the difference is this: "Lay" is a transitive verb. That means it requires an object in the sentence. "Lie" is an intransitive verb. That means it does not require an object. You said you put the book on my desk. "Book" is the object of the sentence, so you need the transitive verb "lay."

Adam: I think I get it now. That seems easy enough.

Ashley: Well, the difference between these two words is a little more complex than that. Let's keep going.

Lay and lie

Lay means "to put or set something down in a flat position." The past tense of lay is laid. Sometimes, it is used with the word "down." For example, "He laid the newspaper down on the table." Or, "The mother laid the baby down for a nap." Notice there is an object in each sentence: "newspaper" in the first, and "baby" in the second.

The verb lie has several meanings. It can mean "to be in a flat position on a surface," such as a bed. With this definition, it is also sometimes used with the word "down." For example, "The doctor told him to lie down on the examination table." Remember, lie is an intransitive verb. The subject is doing the action, not an object.

To make these two words even more confusing, the past tense of lie is lay [L-A-Y]. For example, "Last night, she lay in bed unable to fall asleep." In this example, even native English speakers might use the past tense of lay, which is laid.

Listen to this famous song by Simon and Garfunkel. In this example, they are using the transitive verb lay followed by the direct object me.

Like a bridge over troubled water

I will lay me down

present

past

past participle

transitive

Lay

The chicken lays eggs.

Laid

The workers laid the foundation for new school.

Laid

He has already laid his cards on the table.

intransitive

Lie

Don't lie on the grass.

Lay

She lay on the bed.

Lain

The food had lain on the counter for too long.

Affect and Effect

These next commonly confused words sound - and look - almost the same: affect and effect. But the one-letter difference changes a lot.

Let's start with effect [E-F-F-E-C-T]. Effect can act as a noun or, in rare cases, a verb. As a noun, effect means "a change that results when something happens." For example, "The Chinese economy has an effect on global markets."

Affect [A-F-F-E-C-T] is usually used as a verb. Affect means "to influence." In other words, affect means "to have an effect" on something or someone. For instance, "The Chinese economy affects global markets."

Affect [A-F-F-E-C-T] can also be a noun -- but it is much less common. As a noun, affect is "an emotion or desire that influences behavior."

As mentioned before, effect can also be used as a verb. Used a verb, effect has a similar meaning to affect. It means "to cause something or make something happen." For example, "President Obama has tried to effect a change in the country's health care policy." Again, effect is rarely used as a verb.

If you are confused, just remember this: effect is usually a noun, and affect is usually a verb.

noun

verb

Effect

The law had no effect.

• a change

The president used his power to effect change. (rare)

• to cause

Affect

She took the bad news with little affect. (rare)

• an emotion or desire that influences behavior

The Chinese economy affects global markets.

• To influence

Than and Then

Finally, we have than and then.

Than [T-H-A-N] is both a preposition and conjunction. It is used when comparing things. For example, "I am taller than my sister." Or, "Canada is larger than Mexico."

Then is most often used an adverb. It can mean "at that time." It can also be used when describing what happens next. For example, "I fed my dog, and then I walked my dog."

You can also use then when describing something that must be true if something else is true. We call this an "if/then statement." For example, "If it is raining, then the concert will be canceled."

And that's Everyday Grammar for this week. Join us again next week as we take a look at more examples of commonly confused words!

I'm Ashley Thompson.

And I'm Adam Brock.

Ashley Thompson wrote this article. Adam Brock and Hai Do were the editors.