_______the harvest, farmers are busy _______their work on the field

19. _______the harvest, farmers are busy _______their work on the field.

A. During/ doing             B. While/ to do                                 C. As/ do                                            D. Between/ in doing

20. Peter:  “Do you think that we should use public transportation to protect our environment?”     

      Anna:  “_______.”

A. Yes, it's an absurd idea                                                                     B. There's no doubt about it

C. Of course not. You bet                                                                      D. Well, that's very surprising

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