Examples

Follow the steps in each example to determine whether the compound sentence needs a comma.

1. The town was hit by a driving (rain, and/rain and) many motorists were left stranded.

   Step 1. and is the coordinating conjunction.
   Step 2. The part following and is a complete sentence, so a comma is needed.

2. Several bridges were washed (out, and/out and) some parts of the expressway were under several feet of water.

   Step 1. and is the coordinating conjunction.
   Step 2. The part following and is a complete sentence, so a comma is needed.

3. Emergency road crews worked for (hours, but/hours but) could not repair the damage.

   Step 1. but is the coordinating conjunction.
   Step 2. The part following but is not a complete sentence, so no comma is needed.

4. A (woman, and/woman and) six children in a minivan were swept into a river.

   Step 1. and is the coordinating conjunction.
   Step 2. The part following and is not a complete sentence (instead, it is part of a compound subject), so no comma is needed.

5. The governor asked for federal (aid, but/aid but) it was denied.

   Step 1. but is the coordinating conjunction.
   Step 2. The part following but is a complete sentence, so a comma is needed.