23 Paragraph 2 __________．
24 Paragraph 4 __________．
25 Paragraph 5 __________．
26 Paragraph 6 __________．
27 Before fridges came into use，it was still possible for people to have fresh foods because __________．
28 The invention of the fridge has not provided __________．
29 An important contribution made by the invention of the fridge is that __________．
30 If you stop using the fridge，at least you won't be troubled by the noise __________．