三. 代词

使用代词时请注意其单、复数，主、宾格以及形容词性物主代词和名词性物主代词的用法。

12．He is one of those speakers who make his ideas perfectly clear.

定语从句的先行词是those speakers，为复数，因此从句中的指示代词应为复数，应把his改为their。

13． Whom do you think has left the lights on？

放在疑问句特殊疑问词后的do you think / believe / guess / imagine / suppose等都不参与句子成分，把它们去掉后，疑问词在句中做主语用主格，做宾语用宾格。本句中去掉do you think后缺的是主语，应把Whom改为Who。

14．The boss pretended not to see John and I.

John和I在句中都做的宾语，应把I 改为me。

15．These books are mine; those in the bag are her.

Her是形容词性物主代词，后面应该加名词books，或把her 改为hers。

四. 数词

16．There are fourteen hundreds students in our school.

Hundred / thousand / million / score/ dozen等词前有具体数字时后不加s，前面没有具体数字时在其后加s 和of，表示大约几百几千的概念。如 two hundred students（两百个学生），hundreds of students（成百上千个学生）。例句中应把hundreds 改为hundred。

17．Their school is twice as larger as our school.

表倍数关系的as---as中间只能用形容词或副词的原级。因此把larger改为large.

18．Today’s homework is a five-hundred-words composition.

几个单词由连字符连接而组成的复合形容词中的名词只能用单数，所以把five-hundred-words改为five-hundred-word.

19．Two third of the students in our school are from America.

英语表达中分数的分子用基数词，分母用序数词，分子大于一时分母后要加s，所以就把third 改为thirds.