Ten Bizarre Key Combinations in Word 2013
F8 — Select Text
The F8 serves two text-selection functions. First, it’s used to drop anchor and start selecting text. After you press the F8 key, use the mouse or keyboard text navigation keys to select text. Text is highlighted from the location where you pressed the F8 key to wherever you move the cursor or click the mouse.
F8 can also grow a selection: Press the F8 key twice to select a word, thrice to select a sentence, four times (there is no such word as quarce) to select a paragraph, and five times (quince) to select the entire document.