I think e I don't think non vengono mai usati da soli, ma vengono sempre seguiti da so, come nell'esempio, o da una proposizione come nel caso di I think/I don't think he went to the concert.
Originally a trattoria was a small, often family-run restaurant, offering simple dishes and good value for money. Nowadays many are restaurants in all but name, providing local cuisine at often very high prices in a rustic but elegant setting.