The true sentences about phrases are:
- Phrases can perform the same roles in sentences as individual words.
- Phrases do not contain a complete thought.
The other statements are false:
- Phrases can stand as complete sentences. (This is not true; phrases typically do not stand alone and convey a complete thought.)
- Phrases are always set off with commas. (Not all phrases require commas; it depends on the context and the specific type of phrase.)