78.（单选题）_____ that Bob had been promoted, his friends came to congratulate him.

50.（填空题）I cannot go shopping with you because I have an （appoint）____with my dentist this afternoon.

49.（填空题）The policemen （tell）____not to take any action until they received further order.

48.（填空题）Before the flight takes off, all passengers are asked to （fast）____their seat belts.

47.（填空题）The children （play）____ the violin over there will go on the stage next week.

46.（填空题）After the flood, life was （extreme）____ difficult for the farmers in this area.

45.（填空题）The more challenging the journey is, the （happy）____the young people will feel.

44.（填空题）John not only learnt Chinese but also （know）____the difference between his culture and ours.

43.（填空题）I’ve heard that the musical gtoup will set off for Hong Kong to give a three-day （perform）____.

42.（填空题）For ______ （secure）reasons, passengers are requested not to leave any luggage unattended.

41.（填空题）Society does not know how to deal with the large number of ______ （crime）in prison.