51.那本书毫无价值可言。
[误] that book is invaluable.
[正] that book is valueless.
注：invaluable 和 valueless 一个是在形容词 valuable（有价值的）之前加上否定形容词前缀 in-；另一个是在名词 value（价值）的后面加上否定形容词 -less，但它们的意思却刚好相反。invaluable 是指“非常贵重的，无价的”（highly valuable, precious），其同义词是 priceless；valueless 的意思却是“毫无价值的”，相当于 worthless。现将这两个词用在同一个句子中，以便区别：the book that he considered valueless proved invaluable to us（他认为毫无价值的那本书对我们来说却是无价之宝）。
52. ibm公司一直处在电脑行业的前沿。
[误] ibm is always in the front line of computer industry.
[正] ibm is always at the cuttting edge of computer insustry.
注： front line 是“前线，第一线”的意思，常指最危险或最艰苦的地方。例如：many doctors are in the front line of the fighting against sars（许多医生战斗在抗击“非典”的第一线）。at the cutting edge 最早出现在20世纪50年代，它最初指“锐器的锋利部位”，现在常隐喻“处在（高科技的）最前沿。
53. 一位有经验的教师曾经说，上课之前他觉得如临大敌，上课时他是如履薄冰，只有上完课后他才会如释重负。
[误] an experienced teacher once said that before class he felt as if faced with a formidable enemy, in class he felt like walking on ice, and only after class would he feel relieved.
[正] an experienced teacher once said that before class he felt as if faced with a formidable enemy, in class he felt like walking on eggs, and only after class would he feel relieved.
注： 中文的“如履薄冰”是比喻一个人“做事十分小心谨慎或战战兢兢”，而英语的类似说法却是 walk on eggs 或 tread on eggs，要注意中英文喻体的不同。
54. 我有一个舒适的家。
[误] i have a cozy family.
[正] i have a cozy home.
注： family 和 home 虽然翻译成汉语时都是“家”，但它们在英语中却不是同义词。family 主要指家庭成员；而 home 主要指居住地，即“住宅”。原文中用“舒适的”来修饰“家”，显然是指“舒适的房子”。如果原文是“我有一个和睦的家”，就应该翻译成 i have a harmonious family 了。
55. 每节课老是都会点名。
[误] the teacher will call our names in every period of class.
[正] the teacher will call the roll in every period of class.
注： 英语的“点名”是 call the roll，而 call one's name(s)的意思是“谩骂某人”。rool 有“名册”的意思，又如：remove sb.'s name from the rool（把某人除名）。