49. She set out soon after dark ____ home an hour later.

A. arriving　 B. to arrive　 C. having arrived　 D. and arrived

48. The first textbooks ____ for teaching English as a foreign language came out in the 16^th century.

A .having written　 B. to be written　 C. being written　 D. written

47. The visiting minister expressed his satisfaction with his talks, ____ that he has enjoyed his stay here.

A. having added　 B. to add　 C. adding　 D. added

46. _____ down the radio ---- the baby’s asleep in the next room.

A. turning　 B. to turn　 C. turned　 D. turn

45. How about the two of us ___ a walk down the garden?

A. to take　　 B. take　 C. taking　 D. to be taking

44. Charles Babb age is generally considered ____ the first computer.

A. to invent　 B. inventing　 C. to have invented　 D. having invented

43. The computer center, ___ last year, is very popular among the students in the school.

A. open　 B. opening　 C. having opened　 D. opened

42. “Can’t you read?”　 Mary said ____ to the notice.

A. angrily pointing　　 B. and point angrily　 C. angrily pointed　 D. and angrily pointing

41. ---- I thought you had planed to practise the piano today.

　 ---- I did nothing but _____ letters all day.

A. write　 B. to write　 C. wrote　 D. writing

40. I would appreciate ____ back this afternoon..

A. you to call　 B. you call　 C. your calling　 D. you’re calling