I don't think I know-我不知道啊

Teacher: "John, what is the past participle of the verb to ring?"
John: "What do you think it is, sir?"
Teacher: "I don't think, I KNOW!"
John: "I don't think I know either, sir!"‘
老师：“John，动词ring的过去分词是什么？”。约翰：“你想它是什么呢”？老师：“我不用想，我知道！”。约翰：“我想我不知道”。