Follow the rumble of engines at work! Explore the parts and uses of concrete mixers at work on the construction site. Simple callouts ask students to think in new ways, supporting inquiry-based reading. Titles in the 21st Century Beginning Library introduce students to vocabulary and content they will use for a lifetime as they are prompted to Look , Think , and Connect . Let your young readers discover the joy of reading for information as they grow into lifelong, fluent readers.