Yes. Thanks 5jj, I see.
I can use "how to use" ... so Why cannot I use " when to..." ?
I have moved this to start a separate thread.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
How to ask for directions?
How should I ask for directions?
How can I ask for directions?
How do we ask for directions?
When to use "may" or "might"?
When should I use "may" and "might"?
When do we use "may" and "might"?
I can't use "How to" and "When to" as a question ?
I need to know how to play the game: Correct
How to play the game ? : Incorrect
I need to know when to play the game: Correct
When to play the game ? : Incorrect
Is that right?
Yes. That is right.