Is this a sentence fragment?
During the construction of Mount Rushmore, approximately eight hundred million pounds of rock from the mountain to create the monument.
no yes
A sentence is a group of words that expresses a complete thought.
The band I'm in has been rehearsing daily because we have a concert in two weeks.
A sentence fragment is a group of words that does not express a complete thought.
Rehearsing daily because we have a concert in two weeks.
This fragment is missing a subject. It doesn't tell who is rehearsing.
The band I'm in.
This fragment is missing a verb. It doesn't tell what the band I'm in is doing.
Because we have a concert in two weeks.
This fragment is missing an independent clause. It doesn't tell what happened because of the concert.
This is a sentence fragment. It does not express a complete thought.
During the construction of Mount Rushmore, approximately eight hundred million pounds of rock from the mountain to create the monument.
Here is one way to fix the sentence fragment:
During the construction of Mount Rushmore, approximately eight hundred million pounds of rock were removed from the mountain to create the monument.