English Skills with Readings 8th Edition by John Langan

Exercise 43

Using coordination, subordination, or both, combine each of the following groups of simple sentences into two longer sentences. Omit repeated words. Various combinations are possible, so for each group, try to find the combination that flows most smoothly and clearly.
Gary was leaving the store.
The shoplifting alarm went off.
He had not stolen anything.
The clerk had forgotten to remove the magnetic tag.
The tag was on a shirt Gary had bought.