When to use "I wonder . . ."

When do we use, "I wonder. . ."? 1. We use it when we are using our imaginations and thinking about possibilities. 2. We use it when we don't know something but want to know.

Examples:

1. I wonder how my life would be different if I had never met my wife. 2. I wonder why the sky is blue. 3. I wonder if if my next teacher will be good. 4. I wonder what the name of that song is. 5. I wonder who that woman is.