30. There is no light in the dormitory. They must have gone to the lecture, ____?

42. ____ may help us avoid some diseases.

(  )51. The author’s mother prefers shopping with the author’s sister because the author is slow.

39. The Love U program functions by helping you ____.

19. Not only ____ about the food, she also refused to pay for it.

31. You will have to ____ some outside help or you will never get the job finished in time.

4.

57. 大都市是世界最著名的博物馆之一。你真应该仔细地看看而不是走马观花。

20. Mr. Johnson suggested ____ before details are discussed.

(  )14. Unfortunately, the owner of the elephant refused to pay for the loss of the man.

(  )52. When shopping, it is better to bring the ads with you because some items may actually not be on sale.

(  )54. In order to help readers spend their money more reasonably on Black Friday, the author would like to share a few Black Friday tips.