"Is"
* Singular subjects: Use "is" with singular subjects (one person or thing).
* The dog is sleeping.
* The book is on the table.
* She is happy.
* Third person singular present tense: "Is" is used for the third person singular (he, she, it) in the present tense.
* He is a doctor.
* She is eating.
* It is cold today.
"Are"
* Plural subjects: Use "are" with plural subjects (more than one person or thing).
* The dogs are sleeping.
* The books are on the table.
* They are happy.
* First and second person plural: Use "are" with "we" and "you."
* We are going to the park.
* You are welcome.
* Second person singular: Use "are" with "you" (even though it's singular).
* You are a good student.
Here are some examples to illustrate the difference:
* Correct: The cat is playing.
* Incorrect: The cats is playing. (should be "are")
* Correct: We are hungry.
* Incorrect: We is hungry. (should be "are")
Key Tip: Think of "is" as being for one thing, and "are" for more than one thing.