1.她的独生女儿在山东大学学法律。
　　误：Her only one daughter studies law at Shandong University.
　　正：Her only daughter studies law at Shandong University.
　　析：only作形容词，置于单数名词之前，意为“惟一的、仅有的”，one是多余的。
　　2.他们将在一两天内返回。
　　误：They will return in one or two day.
　　正：They will return in a day or two (或one or two days).
　　析：in a day or two一两天内是固定词组，用a不用one。
　　3.我已完成了三分之二的工作量。
　　误：I have done two-third of the work.
　　正：I have done two-thirds of the work.
　　析：分数表达：一般采用“分子（用基数词） 连字号（可省略） 分母（用序数词 s，分子是one时不加s）。
　　4.这些学生是20世纪末出生的。
　　误：These students were born at the end of the twenty century.
　　误：These students were born at the end of twentieth century.
　　正：These students were born at the end of the twentieth century.
　　析：第几世纪用the 序数词 century表示。
　　5.这是一座20层的大楼。
　　误：This is a twenty-stories building.
　　正：This is a twenty-story building.
　　析：“数词 连字符 单数名词”构成复合形容词。
　　6.我爸爸曾经去过那儿一两次。
　　误：My father has been there one time or two times.
　　正：My father has been there once or twice.
　　析：一次用once，两次用twice，三次或以上用数词 times。
　　7.我们的作业已完成一半。
　　误：Our half homework is done.
　　正：Half our homework is done.
　　析：half our homework是half of our homework的省略式。
　　8.这是8号房间。
　　误：It is 8 Room.
　　正：It is Room 8.
　　析：编号一般用“名词 基数词”表示。
　　9.他们已经学完了前三课。
　　误：They have studied the three first lessons.
　　正：They have studied the first three lessons.
　　析：序数词应放在基数词前。
　　10.我步行到学校要花一个半小时。
　　误：It takes me one and a half hour to get to school on foot.
　　正：It takes me one and a half hours to get to school on foot.
　　析：句中的hour要用复数形式。再如：one and a half months一个半月。
　　11.他们三三两两地来了。
　　误：They arrived by two and three.
　　正：They arrived by twos and threes.
　　析：基数词可用作可数名词复数，用于某些固定词组中。