A tool for assisting a reader in grasping the thought expressed in a group of words on a page is disclosed. The tool is a flexible film card which has a window adjacent contrastingly colored film segments of the card. A group of words may be viewed through the window, and the window may then be moved by the user from one group of words to the next. The groups all around the window may be viewed through the colored segments of the card, thus allowing the reader's eyes to review and anticipate the passages of words which he has read or those which he is about to read while still focusing his attention on the group of words in the window.