Hints: 本期学习的字源：quadr-=four 四，亦作quart- cello 单词不需要大写，单词与例句或不同词条之间换行即可。 注解中详细介绍了单词的拆分与释义，是学习字源分析的重中之重！一定记得听写后来看注解！
quarter quadrant People who are right-quadrant dominant, or more artistic, emotional and spiritual, are very often left-handed. quadrilateral Squares, oblongs and trapezoids are all quadrilaterals. quadruped A majority of mammals are quadrupeds. quartet A string quartet consists of two violins, a viola and a cello.
People who are right-quadrant dominant, or more artistic, emotional and spiritual, are very often left-handed. 右半脑发达的人，也就是比较艺术性、情感性和精神性的人，通常都是左撇子。 Squares, oblongs and trapezoids are all quadrilaterals. 正方形、长方形和梯形都是四边形。 A majority of mammals are quadrupeds. 大部分哺乳类都是四足动物。 A string quartet consists of two violins, a viola and a cello. 弦乐四重奏是由两支小提琴、一支中提琴、一支大提琴组成的。