Answer: they are both independent clauses.
Step-by-step explanation: An independent clause is a sentence that has complete meaning on its own, it has at least a subject, a verb and the modifiers that are necessary to complete the sentence. It is the contrary of a dependent clause, which doesn't have complete meaning on its own. In the given sentences the phrases "he read the book" and "the dog ate the shoe" are independent clauses, because they make complete sense, even without the modifiers.