There are no easy answers to questions brought to us by the rapidly changing world, we can try to turn challenges into opportunities.
Scientists say it may be five or ten years___________ it is possible to test this medicine on human patients.
The girl__________ on the ground __________to me that she had___________ the book on the shelf.
--Did Mary come to your birthday party? --No. I __________ her, but she was away on business.
All the preparations_____, we're ready to start.
--Do you know when the Chinese custom_________ from? --It's hard to say. But its characteristics__________ the Tang Period.