Sing loudly, what is the next line?

Louder, louder, louder. Let us sing loudly! Louder, louder, louder! Turn your pen into a thousand-foot long rainbow, so that you can describe the colorful face of our era, and let thousands of thunder roll in your chest, so that you can sing songs praising the motherland! It comes from "Singing Loudly", a patriotic poem written by my country's famous proletarian poet He Jingzhi in Beijing from June to August 1956! The poems are passionate and powerful.