先週 見た 映画は あまり （　　　）。

Translation: The movie I watched last week was not very interesting. - Grammatical points: Co-occurrence of 'あまり' with negative forms, and tense agreement ('先週' - last week). - Explanation: 1. The adverb 'あまり' demands a negative verb/adjective conjugation (eliminating 'おもしろいです' and 'おもしろかったです'). 2. The timeline is established by '先週見た' (watched last week - past tense). This eliminates the present negative 'おもしろくないです'. 3. Thus, the past negative form 'おもしろくなかったです' (was not interesting) is the only correct answer.