23 Paragraphs 2 and 3__________
24 Paragraph 4__________
25 Paragraph 5__________
26 Paragraph 6__________
27 In most cases of cloud-to-ground lightning the ground's surface __________．
28 One form of lightning that __________ is ball lightning.
29 Cloud-to-ground lightning looks like a ribbon when its lightning channel __________．
30 Although not fully understanding processes of lightning man __________．
