A white dog runs through dried cattails in a snowy field .
The dog is running in the summer sun .
A white dog runs through dried cattails in a snowy field.
The dog is running in the summer sun.
A dog is either running in a snowy field or in the summer sun. The snowy field would not occur in the summer sun.
A dog is either running in a snowy field or in the summer sun . The snowy field would not occur in the summer sun .