A. having spent B. has been spent C. having been spent D. had been spent

　　15. ______ his talk when Mary ran out of the lecture hall.

　　A. Hardly had be begun B. Hardly he had begun

　　C. Hardly he has begun D. He hardly had begun

　　16. Much of the carbon in the earth __________（come）from things that once lived.

　　17. China is not what she __________（use）to be.

　　18. In the past two decades， research __________（expand）our knowledge about sleep and dreams.

　　19. Television ads __________ usually __________（repeat）over and over again.

　　20.Some proverbs _______ （be）in the language for 1，000 years， for example， A friend in need is a friend indeed.

　　21.The nations that __________ actively __________ （involve）in earthquake prediction programs include Japan， China， Russia， and the United States.

　　22.In 1991， after the Gulf War， Bush‘s approval rating reached 91 percent， the highest level recorded since polling __________（begin）in the 1930s.

　　23.Seeing violence on television or reading about it in the newspapers every day __________ （make）us tolerate crime more than we should.

　　24.All the worries they might have felt for him __________ （drive） off by the sight of his cheerful face.

　　25.Little did they realize that they __________（make）an important discovery in science.

　　26. Some people think relations between people _____ （deteriorate） so much that understanding and friendship are almost impossible.

　　27. Let‘s hurry up. She _____ （must， wait） for us.

　　28. Nearly a week passed before the girl was able to explain what _____ （happen） to her.

　　29. Many a writer of newspaper articles __________ （turn） to writing novels during the past decade.

　　30. There __________ （estimate） to be more than 20， 000 overseas domestic servants working in Britain in 1995.

　　31. So far， Irving __________ （live） in New York City for ten years.

　　32. The patient __________ （send） to another hospital before we got there.

　　33. Coffee delays the body clock in the morning， and __________ （advance） it at night.

　　34.Cancer research __________ （make） all over the world in the past twenty years.

　　35.There was a mistake on my paycheck. I __________ （receive） 10more.

　　36.The second half of the nineteenth century __________ （witness） the first extended translation into English of the writings of Eliphas Levi.

　　37. Once harm __________ （do） to the environment， it takes years to have the system recovered.

　　38. This project __________ （accomplish） by the end of 2006 will greatly improve the basic facility of the city.

　　39. Investigations into the cause of the shipwreck show that the ship _________ （sink） the moment it hit the rock .

　　40. If that sounds like far-fetched fantasy， consider these interest