77.Which door does this keyto?

48.He is a man of great knowledge, much can be learned.

47.We should learn from thoseare always ready to help others.

46.We are living in an agemany things are done by computer.

45.The boyI met at the party is my brother * s best friend.

44.Words are windowsyou look into the past.

43.I have a friendmother is a doctor.

42. is known to all, English is one of the most widely used languages in internationalcommunication.

41.The only thingbothered Chris was that his boss never replied to his email.

40.She studied hard at school when she was young, contributed to her success in later life.

39.I don＇t know the reasonMichael didn＇t come yesterday.