Formulating a compound sentence

and

So

But

The teacher handed back our tests, but she didn't score them yet.

We didn't have a ride to the park, so we played at home instead.

My friend couldn't come over to play, so I did something by myself instead.

or

Would you like to eat dinner now, or would you like to go for a walk first?

I forgot my homework, but my teacher said I can bring it in tomorrow for credit.

Tom drove the car, but it ran out of gas before he got to his destination.