Question

which is a run - on sentence? estelle and sharon skipped smooth stones across the still lake. preston has excellent manners he always says \please\ and \thank you.\

Explanation:

A run - on sentence combines two or more independent clauses without proper punctuation or a conjunction. The first sentence is a simple, correctly - structured sentence. The second sentence "Preston has excellent manners he always says 'please' and 'thank you.'" has two independent clauses ("Preston has excellent manners" and "he always says 'please' and 'thank you.'") that are not joined correctly.

Answer:

Preston has excellent manners he always says "please" and "thank you."