Influenza is a viral infection. The flu 26____which caused the 1918 27____was 25 times more deadly than normal and it caused more deaths than the First World War. The consequences of a massive 28____could be disastrous for 29____.For example, a cloud of ash could 30_the sun and the molten lava would destroy everything in its path. 26. A. virus B. chemical C. epidemic D. wave 27. A. impact B. disaster C. pandemic D. eruption 28. A. forest fire B. tsunami C. greenhouse gas D. volcanic eruption 29. A. terrorists B. scientists C. humanity D. mass migration 30. A. block out B. head for C. put out D. wipe out