Interrogative Adverbs

 In English, there are four main interrogative adverbs:

• When: Used to ask about time.
  • Example: When will the train arrive?
• Where: Used to ask about place.
  • Example: Where is the library?
• Why: Used to ask about reason.
  • Example: Why are you late?
• How: Used to ask about manner, method, or condition.
  • Example: How did you get here?

These adverbs are typically placed at the beginning of a question.

Additionally, there are some other words that can function as interrogative adverbs, often in combination with "how":

• How often: Used to ask about frequency.
  • Example: How often do you go to the gym?
• How long: Used to ask about duration.
  • Example: How long will you be staying?
• How far: Used to ask about distance.
  • Example: How far is it to the city center?
• How much/many: Used to ask about quantity.
  • Example: How much does this cost? / How many apples do you want?

These interrogative adverbs help us to ask questions and gather information about various aspects of a situation or event.