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 it 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 bleach, 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 probably 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.
文章精要
本文主要介绍了我们平常所见所用的纸的复杂性,通过介绍用木头和破布料造纸的过程,使我们对纸的类别、属性有了更深入的了解。
1.B
根据题干中的信息提示词cornflake packet,high grade card,可定位到文章第二段,该部分最后提到corn-flake packet在制造过程中比高等级的纸便宜.
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