Form:
If only / I wish + simple past
Example:
If only I knew how to use a computer. (I don’t know how to use a computer and I would like to learn how to use it)
Use:
• To express a wish in the present or in the future.
• The simple past here is an unreal past.
• When you use the verb to be the form is “were”.
Example:
I wish I were a millionaire!