Respuesta :
Answer:
The best way to combine sentences 6 and 7 is "In the summer, school started at 6 a.m., and it did not end until 5 p.m."
Explanation:
Sentences six and seven have the same subject, then they can be linked with a conjunction which in this case is "and" to add a similar idea to the first sentence, it also has a comma as the rule of using commas before conjunctions suggests, and the subject in the second sentence is substituted by a pronoun to avoid unnecessary repetition.