50.There _____ an eraser under the desk. Is it yours ?

　　 A. is　　　　　　　　　　　　　　 B. has　　　　　　　　　　　　　 C. was　　　　　　　　　　　　 D. had

49. The Greens _____ China for five years.

　　 A. has been in　　　　　　　 B. have been in　　　　　　 C. went to　　　　　　　　　　 D. has gone to

48. Paper _____ first invented in China.

　　 A. is　　　　　　　　　　　　　　 B. are　　　　　　　　　　　　　 C. was　　　　　　　　　　　　 D. were

47. He _____ angry because he _____ for a long time.

　　 A. had got…had waited 　　　　　　　　　　　　　　　　 B. got…waited

　　 C. had got…waited　　　　　　　　　　　　　　　　　　　　 D. got…had waited

46. John _____ there since the year before, so he ____ them.

　　 A. had worked…knew 　　　　　　　　　　　　　　　　　 B. had worked….had known

　　 C. worked…knew　 　　　　　　　　　　　　　　　　　　　 D. worked…had known

45. She ____ that ____ it for two days by that day.

　　 A. says…has rained　　　 B. says…had rained　　　 C. said… had rained　　　 D. said…rained

44. They ____for five hours when they ____ in New York.

　　 A. flew…arrived 　　　　　　　　　　　　　　　　　　　　　 B. had flown…had arrived

　　 C. flew…had arrived　　　　　　　　　　　　　　　　　　　 D. had flown…arrived

43. We _____ in a good harvest because we ______ enough rain.

　　 A. didn't get… had had　　　　　　　　　　　　　　　　　　 B. got… had had

　　 C. had got… had bad　　　　　　　　　　　　　　　　　　　 D. got… hadn't had

42. I _____ him a second letter before I _____ from him.

　　 A. wrote… heard　　　　　　　　　　　　　　　　　　　　　　 B. wrote… had heard

　　 C. had written… heard　　　　　　　　　　　　　　　　　　 D. have written… hear

41. Before the news _____ him, he ____ to know about it.

　　 A. reaches… has got　　　　　　　　　　　　　　　　　　　 B. reached…had got

　　 C. reached… got　　　　　　　　　　　　　　　　　　　　　　 D. had reached…got