If you are using SXEmacs under X, you can use the mouse to select text. The selected text will always be highlighted, so just by looking at the text you know what you have selected so far. To select a word just double-click with the left-mouse-button on the word. To select a whole line triple-click anywhere on the line with the left-mouse-button. You can also use the Copy item from the Edit menu on the menu-bar to select text. This kind of selection is called Clipboard selection, See X Clipboard Selection, for more information. To select an arbitrary region, follow these steps:
See Selecting Text with the Mouse, for more information regarding the Mouse and additional mouse operations.