1.The teacher said that the sun revolves around the earth. 2.They are worried about whether they can get there in time. 3.I think it is important for them to complete their tasks on time. 4.The question is whether the book is worth reading. 5.I don't know why Tom didn't come this morning. 6.My advice is that you can not go alone. 7.China today is no longer the China of the past. 8.That is because he didn't understand me. 9.My opinion is that we're leaving tomorrow morning. 10.Who knows what will happen in the future? 希望对你有帮助.