四开本的英文：
quarto

descartes's solution of a depressed quarto equation employs the method of undetermined coefficients
笛卡儿的分解四次方程的解法采用待定系数。

From the table drawer he took out a penholder, a bottle of ink, and a thick, quarto-sized blank book with a red back and a marbled cover
他从桌子抽屉里，拿出了一支笔杆，一瓶墨水，还有本厚厚的四开本日记簿，红色的书脊，大理石纹理的封面。