An interrogative sentence is an asking sentence. Therefore, an interrogative sentence is also called a question.
Use a question mark (?) at the end of an interrogative sentence.
Anytime you begin with an question word, you are writing an asking sentence – an interrogative sentence.
Here are some question words: who? what? where? why? how? when?
A sentence beginning with any one of these question words will be an interrogative sentence.
Who is that man in the red jacket?
What should we eat for dinner tonight?
Where did you put the car keys?
Why did you throw them into the closet?
How many eggs do you want for breakfast?
When can we go for a walk?
Notice that each of these interrogative sentences asks a question. Each of the interrogative sentences also ends with a question mark.