定语从句（7）
(4)“of which”在从句中作宾语、表语及“there be”句型的主语的定语情况：这时“of which”要处于从句句首(目前不作要求) The vector(矢量) sum(和) is the diagonal (对角线) of a parallelogram(平行四边形) of which the given two vectors form(形成) two sides(边). 4 ounces(盎司) of cooked hamburger (煮熟的汉堡包) provides(提供) 30 grams(克) of protein(蛋白质), 67% of which your body(身体) can use.
The line of action(作用) is a line of infinite (无限的) length(长度), of which the force vector(力矢量) is a segment(段). I am particularly(特别) grateful(感激的) to the editors(编辑) of the series(丛书) of which this book is a part. This will not affect the current(电流) that flows in the rest(其余部分) of the circuit(电路) of which this combination(组合) is a part(部分).
All matter(物质) consists of(由…构成) one or more basic(基本的) materials(物质) called elements(元素), of which there are over(超过) 100. The nucleus(原子核) is itself(本身) made up of(由…构成) elementary(基本的) particles(粒子) of which there are two principal(主要的) sorts(种): protons(质子) and neutrons(中子).
二、“of which”在从句中作状语的情况(它一定处于从句句首，“of”是由从句中的动词词组或形容词词组要求的) consist of be capable of be composed of be representative of be made up of be aware of be constructed of be descriptive of be made of be characteristic of be built of be symptomatic of
The force(力) of which we are aware(知道的) in our daily life is the force of gravitational attraction(重力) exerted(施加) on every physical body(物体) by the earth. The two elements(元素) of which water is made are oxygen(氧) and hydrogen(氢).