| A | B |
| Theo will bring the potato salad and Sarah will bring the apple juice. | Theo will bring the potato salad, and Sarah will bring the apple juice. |
| Congress passed the bill but I believe the president vetoed it. | Congress passed the bill, but I believe the president vetoed it. |
| I went to bed early for I had a big day ahead of me. | I went to bed early for, I had a big day ahead of me. |
| The storm brought heavy rain but a tornado did the most damage. | The storm brought heavy rain, but a tornado did the most damage. |
| The sailboat was almost hidden by the fog yet we could see part of the mast. | The sailboat was almost hidden by the fog, yet we could see part of the mast. |
| Would you like to play checkers or would you like to go to the lake instead? | Would you like to play checkers, or would you like to go to the lake instead? |
| I called my friends and told them the news. | No comma because there is a compound verb, not 2 independent clauses in a compound sentence. |
| Jim practiced the piano piece all month for he wanted to do well at the recital. | Jim practiced the piano piece all month, for he wanted to do well at the recital. |
| Many people are used to celebrating New Year's Day on January 1 but the Chinese New Year begins between January 21 and February 19. | Many people are used to celebrating New Year's Day on January 1, but the Chinese New Year begins between January 21 and February 19. |
| The lake contains fish and is home to several alligators. | Correct. It does not contain 2 independent clauses. |
| The old oak tree shaded the house but the shade kept the grass from growing. | The old oak tree shaded the house, but the shade kept the grass from growing. |
| I wanted to buy a camera so I mowed yards in the neighborhood to earn extra money. | I wanted to buy a camera, so I mowed yards in the neighborhood to earn extra money. |
| Pam swims often and jogs daily. | Correct. No comma needed because it is not two independent clauses. |
| Pam swims often and she jogs daily. | Pam swims often, and she jogs daily. |