综合学术英语教程1 答案Unit 1 Global Warming Keys to the ExercisesReading 1. Skim Reading 1 and answer the questions below. 1) What four disasters are more frequent than in the past according to paragraph one? Hurricanes, flooding, droughts and forest fires. 2) What are two harmful effects of global warming on animals and nature? The number of animals per species has been decreasing and some animals spread diseases to human beings. 3) What are the two effects of ozone