I don't know What Tom did last night. Can you tell me what you were doing at nine last night? I think you are right. Nobody knows what will happen in a hundred years. I think Tom has gone to the library. Tom told me he went to the park last night. She asked me where I had been before. She said she would come back the next day .
主句一般现在时,从句适当时态 1.I don't know whether he will come 2.I hope the day that there will be no pressure 主句一般过去时,从句用过去式一种 1.I remembered he had gotten earli than me 2. The bus didn't go until every was ready