端午节是古老的传统节日，形成于中国哪段历史时期？（）

Dear Dowe, How are you It has been a long time since we last contacted each other. Now, I'm writing this E-mail to introduce a traditional Chinese festival--Dragon Boat Festival.
The Dragon Boat Festival, also called the Duanwu Festival, is celebrated on the fifth day of the fifth month according to the Chinese calendar. The exact origin of Dragon Boat Festival is not clear, but one traditional view is that it is celebrated in honor of the Chinese patriotic poet Qu Yuan who is said to have committed suicide by drowning himself in a river. So the local people sat on long, narrow paddle boats called dragon boats, and threw bamboo leaves filled with cooked rice into the river to feed the fish for protecting Qu' s body. This later on turned into the custom of eating rice dumplings also called zongzi and holding dragon boat races on this day. The rice dumplings are made of glutinous rice, meat and so on. They are very delicious.
I hope you can come to China and spend the Dragon Boat Festival with me.
Best wishes,Chen Ming