假如你是李華，你的外國筆友Jim對中國長城很感興趣。請你給他根據以下要點給他寫一封信，簡要介紹長城的一些情況。
歷史：有兩千多年的歷史。
特點：世界上最長的城墻，長6000多千米；建筑材料主要為石頭、磚頭，修建工作都是人工進行；主要用于防御外來入侵者（invader），沿墻每隔幾百米就有烽火臺（watchtower）。
現狀：世界著名旅游景點之一，每年吸引許多國內外游客到長城觀光旅游。
（1）注意：詞數80左右；
（2）可適當增加細節，以使行文連貫；
（3）信的開頭和結尾已給出，不計入總詞數。
Dear Jim，
    Learning that you show great interest in the Great Wall，I'm writing to share some information with you.
______________
Yours sincerely，
Li Hua

【考點】書信類．

【答案】Dear Jim，
Learning that you show great interest in the Great Wall，I'm writing to share some information with you.
The Great Wall，which is more than 6，000 kilometers long，is the longest wall in the world.With a history of over 2，000 years，it was made of stones and bricks.Besides，almost all the construction was done by hand without any machine.As the wall was built to defend the country against foreign invaders，there were watchtowers every few hundred meters along the wall.Now，the Great wall is one of the most famous places of interest in China，attracting many tourists from home and abroad every year.
As is described above，I believe it is worthwhile to pay a visit to the Great Wall.
Yours，
Li hua