(四) Who和which的区别
which指代事物或者动物，who指代人
who/whom son往往要改为whose son, whose可以指代事物
例：The human body contains more than six hundred muscles who
A B
account for approximately forty percent of the body weight.
C D
分析：B错，应改为which或that。先行词不是指人，而是指物，关系代词不能用who,故改为which或that。
人体前面加定冠词the, account for 占有多大的比例，解释说明
(五) that和which的区别
介词后面使用which, 而不用that, in that除外
例：When television was first introduced, the extent to that it
A B
would affect society could not have been foreseen.
C D
分析：B错，应改为which。The extent to which, 介词加which(引导定语从句)，影响社会的程度没有被预见
(六) 定语从句的特殊省略
Reason后面有定语从句，中间往往省略why,
Time后面有定语从句，中间往往省略when
I do remember the time I heard the sweetest voice in the wild world.
way后面有定语从句，中间省略了in which
例：Research on pain has been neglected, although the mainly
A B
reason people take medicine is to relieve pain.
C D
分析：B错，应改为main。mainly为副词，不能修饰后面的名词，故改为形容词main。句子中people take medicine修饰reason，定语从句引导词被省略
例：Commercial expansion from city to suburb has
affected the way people in the United States----.
(A) living and working
(B) they live and work
(C) live and work
(D) to live and to work
分析：选择C, the way people....影响了人们生活和工作的方式