||How Big, etc.
- I am 18 years old. How old are you?
- Common Error: I have 18 years. How old do you have.
- Common Error: What big are the boxes.
The word big
is an adjective, so you use how
You can use what
with a noun to express similar ideas:
- What age are you? What is your age?
- What size are the boxes.
- How beautiful your house is!
- Common Error: How beautiful is your house!
This is not a question; it is what you say when you are impressed (like here), surprised, shocked, etc. Notice the word order. It is not the same as for a question.
- How tall you are! How old are you?
- How moody you seem today!
- What is your new boyfriend like?
- Careful: How is your new boyfriend?
What ... like? is the most common way to ask about someone's personality, but you will also hear: How is your new boyfriend?
How in this sense is more common when you want to know about his health: "Is he sick or not?"