五、词汇。用所给单词的正确形式填空。（每小题1分，共10分）

46. I will _______ (certain) lend my bike to you.

47. The company tries hard to _________ (satisfied) its customers.48. When you do something wrong, you need to make _________(apology).

49. The shop mainly sells ________ (electricity) products.

50. The country has made great progress in science and _______ (technologic).

51. The mother was so worried about his son, but she didn't know what _________ (do).

52. She has trouble _______ (tell) red from green.

53. He is angry now. You’d better ______ (leave) him alone.

54. Nowadays, a lot of people worry about ______ (get) a job.

55. I forgot _______ (call) you yesterday because I was too busy