改出下列句中的错误（每句中各有一个错误）
1.It is well-known that English is one of the world's most widely used language.
2.I haven't decided if to go to Beijing or to leave for Beijing.
3.The harder you'll study, the greater progress you'll make.
4.I am pleased with that you have done and what you have said.
5.Don't forget writing to me as soon as you reach Beijing in two days.
6.Aunt Liu is lonely, so we are going to have someone else to live with her.
7.I find it hard to believe what the writer says in his recent book thought it sounds reasonably.
8.Two days ago, I went to my uncle, my aunt told me that he had left for Australia on business.
9.Those who have joined in the army will get two months' strict training before they got to the front.
10.Reading newspapers every day help us to keep up with the changing wrold.
11.Thousands of men died and buried under the Great Wall when it was built.
12.The teacher told us that we are going to hand in our homework the next day.
13.They talking with the matter all through the night.
參考答案:12. are-were
11.building
4.please
bu hui le
bu zhi dao dui bu dui a
参考资料：夢花落紛飛
