---- Why does the river smell terrible? ---- Because large quantities of water______.
Traditional Chinese medicine is thousands of years old and has developed _______ time.
_______ with the Japanese government, some Chinese people decided not to buy products from Japan any more.
After I went abroad for further study, _______ of my parents lived with me.
When Helen saw her tutor nod _______ to her, she calmed down and went on with her performance.
Before joining the Department of Defense, Mr. Panetta _______ as director of the CIA from February 2009 to June 2011.