现在进行时描述正在进行的动作 — 英语填空题
题目
Nora usually reads in the school library after class. Today, she and her brother are in the art room, and their father is there with them. Look! Nora and her brother ___ (prepare) a display, while their father ___ (wait) beside the door. Fill in the blanks with the correct forms of the verbs.