To ask "how long" in Engpsh, you can say "for how long" or "how long does it take." Here are some examples of how to use these phrases:

For how long have you been studying Engpsh?
How long does it take to get to the airport by car?
For how long will you be staying in the city?
How long does it take to learn a new language?

You can also use "how long" to ask about the duration of an event or activity. For example:

How long does the concert last?
How long does the movie run for?

I hope this helps! Let me know if you have any other questions.