Scientists say it may be a few years ______ it is possible to test the new medicine on patients.
It has to be a place we can do lots of exercise.
Yunnan is colorfulmillions of people come to enjoy themselves every year.
I think Hangzhou is one of ________ in China
--Can I use your mobile phone? --Of course..
—______ does your school have sports meeting? —Twice a year.