The fact "a board is for stacking with bricks to make a cheap bookshelf." is illustrated with the story:1. A bookshelf made of bricks and boards is "hand-made". 2. Stacking bricks raises "level ground"3. A horizontal board placed on stacked bricks makes a shelf.4. A shelf is good to hold books or other articles.5. Students use bricks and boards for shelves because they are usually poor.