I'm really concerned ahout you. If something _______ happen to you  call me at once. 

Nobody knows how people first came to these islands. They _____ from South America on rafts.

I wish I____ my uncle yesterday.

—What would you wish to do if you were a college student again? —That's very hard to say, but I wish I___________ when I was a college student.

I enjoyed the movie very much. I wish I ______ the book from which it was made.