How to translate several sentences of English subjunctive mood ~ ~ ~

1. If only I were as wise as you!

That German girl speaks Greek fluently, as if she were a native Greek.

If only I hadn't told him our secret!

How I wish I hadn't spent so much money!

I hope I can go to the moon one day!

6. The teacher was very angry and seemed to kill me.

I hope I can help you!