1、A） We are surrounded by so much paper and card that it is easy to forget just how complex it is. There are many varieties and grades of paper materials, and whilst it is fairly easy to spot the varieties, it is far more difficult to spot the grades.B） It needs to be understood that most paper and ca
2、rd is manufactured for a specific purpose, so that whilst the corn-flake packet may look smart, it is clearly not something destined for the archives. It is made to look good, but only needs a limited life span. It is also much cheaper to manufacture than high grade card.C） Paper can be made from an
3、 almost endless variety of cellulose-based material which will include many woods, cottons and grasses or which papyrus is an example and from where we get the word paper. Many of these are very specialized, but the preponderance of paper making has been from soft wood and cotton or rags, with the b
4、ulk being wood-based.Paper from WoodD） In order to make wood into paper it needs to be broken down into fine strands. Firstly by powerful machinery and then boiled with strong alkalies such as caustic soda, until a fine pulp of cellulose fibers is produced. It is from this pulp that the final produc
5、t is made, relying on the bonding together of the cellulose into layers. That, in a very small nutshell, is the essence of paper making from wood. However, the reality is rather more complicated. In order to give us our white paper and card, the makers will add bleach and other materials such as chi
6、na clay and additional chemicals.E） A further problem with wood is that it contains a material that is not cellulose. Something called lignin. This is essential for the tree since it holds the cellulose fibres together, but if it is incorporated into the manufactured paper it presents archivists wit
7、h a problem. Lignin eventually breaks down and releases acid products into the paper. This will weaken the bond between the cellulose fibers and the paper will become brittle and look rather brown and careworn. We have all seen this in old newspapers and cheap paperback books. It has been estimated
8、that most paper back books will have a life of not greater than fifty years. Not what we need for our archives.F） Since the lignin can be removed from the paper pulp during manufacture, the obvious question is why is it left in the paper? The answer lies in the fact that lignin makes up a considerab
9、le part of the tree. By leaving the lignin in the pulp a papermaker can increase his paper yield from a tree to some 95%. Removing it means a yield of only 35%. It is clearly uneconomic to remove the lignin for many paper and card applications.G） It also means, of course, that lignin-free paper is g
10、oing to be more expensive, but that is nevertheless what the archivist must look for in his supplies. There is no point whatsoever in carefully placing our valuable artifacts in paper or card that is going to hasten their demise. Acid is particularly harmful to photographic materials, causing them t
11、o fade and is some cases simply vanish!H） So, how do we tell a piece of suitable paper or card from one that is unsuitable? You cannot do it by simply looking, and rather disappointingly, you cannot always rely on the label. Acid-free might be true inasmuch as a test on the paper may indicate that i
12、t is a neutral material at this time. But lignin can take years before it starts the inevitable process of breaking down, and in the right conditions it will speed up enormously.I） Added to this, as I have indicated earlier, paper may also contain other materials added during manufacture such as ble
13、ach, china clay, chemical whiteners and size. This looks like a bleak picture, and it would be but for the fact that there are suppliers who will guarantee the material that they sell. If you want to be absolutely sure that you are storing in, or printing on, the correct material then this is probab
14、ly the only way.J） Incidentally, acids can migrate from material to material. Lining old shoe boxes with good quality acid-free paper will do little to guard the contents. The acid will get there in the end.Paper from RagK） Paper is also commonly made from cotton and rag waste. This has the advantag
15、e of being lignin-free, but because there is much less cotton and rag than trees, it also tends to be much more expensive than wood pulp paper. You will still need to purchase from a reliable source though, since even rag paper and card can contain undesirable additives.L） A reliable source for qual
16、ity rag papers is a recognized art stockiest. Many water color artists insist on using only fine quality rag paper and board.M） The main lesson to learn from this information is that you cannot rely on purchasing archival materials from the high street. The only safe solution is to purchase from spe
17、cialist suppliers. It may cost rather more, but in the end you will know that your important and valuable data and images have the best home possible.长篇阅读（2）How to Make Attractive and Effective PowerPoint PresentationsA） Microsoft PowerPoint has dramatically changed the way in which academic and bus
18、iness presentations are made. This article outlines few tips on making more effective and attractive PowerPoint presentations.The TextB） Keep the wording clear and simple. Use active, visual language. Cut unnecessary wordsa good rule of thumb is to cut paragraphs down to sentences, sentences into ph
19、rases, and phrases into key words.Limit the number of words and lines per slide. Try the Rule of Five-five words per line, five lines per slide. If too much text appears on one slide, use the AutoFit feature to split it between two slides. Click within the placeholder to display the AutoFit Options
20、button （its symbol is two horizontal lines with arrows above and below）, then click on the button and choose Split Text between Two Slides from the submenu.C） Font size for titles should be at least 36 to 40, while the text body should not be smaller than 24.Use only two font styles per slideone for
21、 the title and the other for the text. Choose two fonts that visually contrast with each other. Garamond Medium Condensed and Impact are good for titles, while Garamond or Tempus Sans can be used for the text body.D） Embed the fonts in your presentation, if you are not sure whether the fonts used in
22、 the presentation are present in the computer that will be used for the presentation. To embed the fonts: （1） On the File menu, click Save As. （2） On the toolbar, click Tools, click Save Options, select the Embed TrueType Fonts check box, and then select Embed characters in use only.E） Use colors sp
23、aringly; two to three at most. You may use one color for all the titles and another for the text body. Be consistent from slide to slide. Choose a font color that contrasts well with the background.F） Capitalizing the first letter of each word is good for the title of slides and suggests a more form
24、al situation than having just the first letter of the first word capitalized. In bullet point lines, capitalize the first word and no other words unless they normally appear capped. Upper and lower case lettering is more readable than all capital letters. Moreover, current styles indicate that using
25、 all capital letters means you are shouting. If you have text that is in the wrong case, select the text, and then click Shift+F3 until it changes to the case style that you like. Clicking Shift+F3 toggles the text case between ALL CAPS, lower case, and Initial Capital styles.G） Use bold or italic t
26、ypeface for emphasis. Avoid underlining, it clutters up the presentation.Dont center bulleted lists or text. It is confusing to read. Left align unless you have a good reason not to. Run “spell check” on your show when finished.The BackgroundH） Keep the background consistent. Simple, light textured
27、backgrounds work well. Complicated textures make the content hard to read. If you are planning to use many clips in your slides, select a white background. If the venue of your presentation is not adequately light-proof, select a dark-colored background and use any light color for text. Minimize the
28、 use of “bells and whistles” such as sound effects, “flying words” and multiple transitions. Dont use red in any fonts or backgrounds. It is an emotionally overwhelming color that is difficult to see and read.The ClipsI） Animations are best used subtly; too much flash and motion can distract and ann
29、oy viewers. Do not rely too heavily on those images that were originally loaded on your computer with the rest of Office. You can easily find appropriate clips on any topic through Google Images. While searching for images, do not use long search phrases as is usually done while searching the web-us
30、e specific words.J） When importing pictures, make sure that they are smaller than two megabytes and are in a .jpg format. Larger files can slow down your show. Keep graphs, charts and diagrams simple, if possible. Use bar graphs and pie charts instead of tables of data. The audience can then immedia
31、tely pick up the relationships.The PresentationK） If you want your presentation to directly open in the slide show view, save it as a slide show file using the following steps. Open the presentation you want to save as a slide show. On the File menu, click Save As. In the Save as type list, click Po
32、werPoint Show. Your slide show file will be saved with a ppt file extension. When you double-click on this file, it will automatically start your presentation in slide show view. When youre done, PowerPoint automatically closes and you return to the desktop. If you want to edit the slide show file, you can always open it from PowerPoint by clicking Open on the File menu.L） Look at the audience, not at the slides, whenever possible. If using a laser pointer, dont
