1. Tabs are generally omitted. If the chapter heading in the tab is used as a heading at the beginning of the new chapter, definitely omit the tabs. No TN is needed.
2. Headings are brailled the first time they appear and are generally not repeated as the material that pertains to them continues. However, if the same heading is used again after some other material under a different heading, repeat it in braille as in print.
3. I agree.
4. The bold letters are simple abbreviations to be used for word identification. The capital letters are enough, especially since the letters are well-explained in the text. The single cap S is preceded with a letter sign followed by the cap indicator. The other letters do not need the letter sign, because the double caps make it clear that these are just letters and none of them are contractions. DO is not the word do (as in DO something) and that is made clear in braille with presenting the letters separately with double caps. [simbraille],,do[/simbraille]
I suggest retaining the bold in the exercise itself because both both and italics seem to be used in the book, judging by the other material on this page.
An image file is just fine and a .pdf is not necessary as long as the image is good enough to be read. There is not problem in reading this one and it was very helpful. Thanks for including it.
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