A group of words with a subject and verb that does not express a complete thought is called

clauses, hope this helps!

Explanation:

Clauses. ... An independent clause is a group of words that contains a subject, a predicate, and a complete thought. A dependent clause is a group of words that contains a subject and a predicate, but does NOT express a complete thought.

source: http://webapps.towson.edu/ows/sentelmt.htm

to save the day, harry must get past a scary three-headed guard dog.

she has clear pronunciation