A conditional sentence is usually composed by two parts: the if-clause (or conditional clause) that expresses the condition, and the main clause that expresses the consequence of that condition.
If only and wish are used to show our regrets or wishes in the past and the present. It also shows wishes about future.
We use wish and if only to express our wishes and regrets. They have this structures:
- Past wishes/regrets: If only/Wish + past conditional + …
- Present wishes/regrets: If only/Wish + past subjunctive + …
- Future wishes/regrets: If only/Wish + present conditional + …
- I wish you would have a serious character.
- If only he had had some responsibility and punctuality.
- I wish Laura could recover her strength again.
We use if only and wish when we would like things to be different.
It has a relation with conditional sentences, but the usage of these conditionals differs. We use:
- Past wishes/regrets: to show our regrets and wishes in the past;
- Present wishes/regrets: to show our regrets and wishes in the present;
- Future wishes/regrets: to show our wishes that may occur in the future.