__________ the zoologists tried to prove was that the photo of the South Chha Tiger had been staged or technologically dealt with.
17. The boy sat at the top of the hill, looking at the valley ______.
16. I have never heard such a beautiful song _____.
15. With the development of West China, many technicians are _____ needed there in recent years.
14. China has a lot of coal and oil, and it is rich in other rare minerals ______.
13. --- How long has he been in the army? --- Oh, he joined the army as far ____ as 1997.