I will assume that "found sentences" actually refers to "compound sentences".
Answer:
My family and I went to Brazil for the summer holidays. We stayed at a hotel in Rio de Janeiro, and we had a great time. <u>We weren’t able go to the beach on the first couple of days because it was raining. When the rain stopped, however, we couldn’t have enough of the beautiful ocean and light-colored sand.</u> At the beach, there are some “barracas” selling fresh shrimps, but we had to buy them sneakily. <u>Since my father is allergic, we did not want to tempt him into having some as well.</u> I tried to learn how to surf, but it is harder than I had imagined. I hope to go back in the future.
Explanation:
A complex sentence is formed by joining an independent clause and a dependent one. A dependent clause needs the independent one to give it context, so that it makes sense. It does not express a complete thought on its own. The dependent clause is set off by a subordinating conjunction (since, because, when, etc.) The complex sentences in the answer above are all underlined.
A compound sentence is formed by joining two independent clauses connected by a coordinating conjunction - for, and, nor, but, or, yet, so. The compound sentences int he answer above are all in bold.