这里的 unlock, beneath, produce, fold, ... 一看就不是你一个中学生的会想到的词汇, 而且句型过于复杂。帮你改一下:
My teacher opened a cupboard next to the bookcase and took out a book. He put the book onto the desk. He only opened the last page and kept his hand on the rest, so that every other lines of the text were covered.