Yang Yunjing is a tour guide volunteer in Tibet.  She went there five times as tour guide . Her parents and friends couldn't understand why she chose the hard work. But facing all the confusion( ), Yang just smiled and said, "Tibet is full of charm ." When Yang finished her studies at the university three years ago, she had two choices: being an exchange student in Germany, or volunteering for Tibet. Finally, she chose the latter . Her father said, " I'll support(  ) you. But no matter what happens, you have to face it on your own." When Yang went to Tibet for the first time, she got a " gift" -- altitude sickness( ). She had to be in hospital, but she didn't tell her parents about it. During her volunteer work, she did a great job because she worked very hard. One day when she returned to her room at night, she got a call from another tour guide volunteer. She told her that a woman of the group was badly hurt when climbing the mountains. Hearing that, Yang went to the hospital quickly and decided to stay there and look after the woman. Yang learnt a lot from the volunteer experience." As long as I think of the sky there, I can laugh it off, no matter what difficulties I may meet," she said. When did Yang Yunjing start to work as a volunteer?
Three years ago. Four years ago. Five years ago. Eight years ago.