The training was hard work but there were lighter moments, said the elder sister Li Ziye.
She said they were trained to smile with eight teeth exposed and look at the camera flashes without blinking.
"We should not blink even if tears come out," Li Ziye said, with eyes opened wide.
"People always confused by us. I was always blamed by the teacher when my sister did something wrong. Some even thought there was a mirror when we were sitting face to face," the younger one Li Xiaoye said, chuckling.
Many girls have made good friends during these days because of the shared experiences.
"I've made many new friends here. They helped me a lot, which touched me sometimes deeply," Yang Xu said.
"The victory ceremony will be the faces of China's Olympics as a necessary part of the Games," said Cai Fuchao, vice mayor of Beijing, at a start-up ceremony for volunteers on Sunday.
The ceremonies had been designed with many traditional Chinese elements, the deputy division chief Wang Ning said.
The hostesses had been trained to be beauties both inside and outside, Wang said. The young women, with a classical Chinese temperament, would send messages of Chinese implicit beauty in each simple move as taught in the classes, she said.
Their silk costumes were also designed with traditional Chinese cultural images such as blue-and-white porcelain, embroidery and jade.
The ladies were not only beauties, but well-educated beauties, said Wang who had added classes like security, making-up skills and handling the media.
"All of them can communicate in English without any problem, and some even can speak other foreign languages such as Spanish," Wang said.
They had all been arranged to each single post in every venue and each of them know her duties well.
"We have labored so much, simply to give for a few minutes a good impression at the Olympic victory ceremony as we want to show the most beautiful aspect of oriental ladies across the world," said the twin sister Li Ziye, with a gentle smile.