Unlike previous Word versions, Word 2010 offers a set of viewing options. Tale Full Screen mode as an example, in this mode you have all features which can abet you in reading the text easily. The upper lane in this mode carries navigation controls along with highlighting tool to promptly highlight the text while reading the document. Apart from this, you can comment out specific part of document.
To view document in full screen for easier reading, open the document and navigate to View tab, under Document Views group, click Full Screen Reading.
This will change the view to Full Screen.
As shown in the screenshot, from upper part of the window, you can pick out highlighter to mart out text and add comments.