worldwide over the past period from 1960s to 1990s. 2) To be concrete, there were only 16 terrible natural disasters, causing 300,000 deaths in 1960s while the ratios went up respectively to 131 and 1, 100,000 in 1990s. 3)The changes are disturbing, so it is necessary for us to go into the whys and wherefores of them first.4) Some changes, such as those in earthquakes and volcanic eruptions result from the movement of plates along the weaknesses in the earths crust, but many others have much to do with mans activities. 5)In the first place, mans mindless and excessive ex of natural resources has done a lasting damage to the ecosystem, only to invite more floods, landslides and mud-rock flows. 6)The rare flood to which China was subjected in 1998 is typical of the evil seeds man had sowed for himself. 7) In the second, in order to feed their more and larger families, people from all over the world have had to overwork their farming land as well their grassland, which in turn has accelerated the desertification of the land on which they have been relying for existence. 8)In the third, man's blind application of scientific findings has caused unfavorable and permanent changes in the global living environment. 9)Among these changes are the depletion of ozone layer, the worsening of greenhouse effect, the recurrence of hurricanes and the extinction of more species. 10) The list of causes could go on, but they are already enough to ave not only made it impossible for the natural systems to recover their balance but also made it harder for man to ensure his better survival. 12)If allowed to run its course, I am afraid this trend will certainly bring more serious threats to all the living things on the Earth, mankind included Section B I Reading skills ng is to read quickly in order to get the general idea of a passage. Skimming requires the reader to note only information and clues which provide an idea of the central theme or topic of a piece of Skimming When you skim, you read only selected sentences in order to get the main idea. You should also use textual clues such as italicized or underlined words, headlines or subtitles, spacing, paragraphing, etc. Do not read every word or sentence. Once you have a general idea about an article you may decide to read the entire selection carefully, or only to scan for specific pieces of information in order to answer questions which have occurred to you When you skim, you probably have to move your eyes faster than when you scan although the same steps of reading are involved Of course, the key step is to decide what information you want to know, and then try to skim for it The following are some examples from Passage A in this unit to explain how to ski articular information that a reader is interested in shall I find the information about earthquake prediction, prevention and preparation?ow:Where After having a brief look at the title of the reading passage, you might want to kne To skim for the places for the information in question, the reader actually just needs to read the first sentence of each paragraph in the text. Sentence l, Paragraph I tells him/her that this is the place for information about earthquake prediction; Sentence 1, Paragraph 2 for information about earthquake prevention; the first sentence of Paragraphs 3, 4, 5, 6 for information aboutworldwide over the past period from 1960s to 1990s. 2) To be concrete, there were only 16 terrible natural disasters, causing 300,000 deaths in 1960s while the ratios went up respectively to 131 and 1,100,000 in 1990s. 3) The changes are disturbing, so it is necessary for us to go into the whys and wherefores of them first.4) Some changes, such as those in earthquakes and volcanic eruptions, result from the movement of plates along the weaknesses in the earth’s crust, but many others have much to do with man’s activities. 5) In the first place, man’s mindless and excessive exploitation of natural resources has done a lasting damage to the ecosystem, only to invite more floods, landslides and mud-rock flows. 6) The rare flood to which China was subjected in 1998 is typical of the evil seeds man had sowed for himself. 7) In the second, in order to feed their more and larger families, people from all over the world have had to overwork their farming land as well as their grassland, which in turn has accelerated the desertification of the land on which they have been relying for existence. 8) In the third, man’s blind application of scientific findings has caused unfavorable and permanent changes in the global living environment. 9) Among these changes are the depletion of ozone layer, the worsening of greenhouse effect, the recurrence of hurricanes and the extinction of more species.10) The list of causes could go on, but they are already enough to indicate that these changes are producing more and more negative effects on the world. 11) They have not only made it impossible for the natural systems to recover their balance but also made it harder for man to ensure his better survival. 12) If allowed to run its course, I am afraid, this trend will certainly bring more serious threats to all the living things on the Earth, mankind included. Section B I. Reading Skills Scanning involves searching for details or isolated facts (see Unit 1) whereas skimming is to read quickly in order to get the general idea of a passage. Skimming requires the reader to note only information and clues which provide an idea of the central theme or topic of a piece of writing. Skimming When you skim, you read only selected sentences in order to get the main idea. You should also use textual clues such as italicized or underlined words, headlines or subtitles, spacing, paragraphing, etc. Do not read every word or sentence. Once you have a general idea about an article you may decide to read the entire selection carefully, or only to scan for specific pieces of information in order to answer questions which have occurred to you.When you skim, you probably have to move your eyes faster than when you scan although the same steps of reading are involved. Of course, the key step is to decide what information you want to know, and then try to skim for it. The following are some examples from Passage A in this unit to explain how to skim for the particular information that a reader is interested in. After having a brief look at the title of the reading passage, you might want to know: Where shall I find the information about earthquake prediction, prevention and preparation? To skim for the places for the information in question, the reader actually just needs to read the first sentence of each paragraph in the text. Sentence 1, Paragraph 1 tells him/her that this is the place for information about earthquake prediction; Sentence 1, Paragraph 2 for information about earthquake prevention; the first sentence of Paragraphs 3, 4, 5, 6 for information about