几种特殊的定语从句

几种特殊的定语从句

■since / until / by when引导的定语从句

定语从句中有一类是since / until / by when引导的定语从句, 这类比较特殊的定语从句，一般都可整合为and连接的并列句。and since / until / by then= since / until / by when

借助并列句分析解此类定语从句，就会简单易懂易记。

【典型例题1】

The book was written in 1946, _______ the education system has witnessed great changes.

A. when                           B. during which     

C. since then                    D. since when

【解析】句意：该书写于1946年，从那以后教育制度已经历了 巨大变化。因从句中“has witnessed”是完成时，而只有含 since引导的时间状语句子才用完成时，故此句可改写：

The book was written in 1946, and since then the education system has witnessed great changes.

【典型例题2】

The baby is due in May, _______ the new house should be finished.

A. by then                        B.  which   

C. by when                       D. since when

【解析】句意：“那个婴儿五月将出生，到那时他 / 她家的新房应该能装修完毕了。”故此句可改写：

The baby is due in May, and by then the new house should be finished.

【典型例题3】

I am going back to my hometown this summer, ________I will have enough time to buy a car.

A. by then                             B.  which      

C. by when                           D. since when

【解析】句意：今年夏天我打算回家乡，到那时我就会有足够的时间买辆车。从句的时态是将来时，所以排除D，从句中的成分是完整的，排除Ｂ，by then不能引导从句，by when在句意和时态上都吻合题意，相当于and by then,故故此句可改写：

I am going back to my hometown this summer, and by then I will have enough time to buy a car.

【典型例题4】

Tom has been living a comfortable life, _______his parents run away due to heavy debts.

A. until then                          B. until when     

C. since then                         D. since when

【解析】句意：Tom在父母亲的照顾下，过着富裕的生活，直到他父母由于沉重的债务跑掉了。until then 和since then 不能引导从句，since when时态需要用完成时，正确答案是B。

本句可以改写为：

Tom has been living a comfortable life, and until then his parents run away due to heavy debts.

■which + n. 引导的定语从句

which可以加概括意义的名词，引导定语从句。

and during / by that time=during / by which time 在那段时间

and in that case = in which case 在那种情况下

and at that point = at which point 在那时

and that language = which language 那种语言

【典型例题1】

He can speak German, ________language I can only follow with difficulty.

A. that                               B. whose         

C. which                            D. what

【解析】句意：他会说德语，那种语言我要很费力地才能听懂。A,D不能引导非限制性定语从句，whose和language的关系不是所属关系，所以答案是which 。此句可改写：

He can speak German, and I can only follow that language with difficulty.

【典型例题2】

She may be late, ________we ought to wait for her.

A. in which case                    B. in that case

C. where                               D. from where

【解析】句意：她可能迟到，那种情况我们该等她。C,D与题意不吻合，in that case不能引导从句，in which case 能引导从句，而且和词组吻合。本句可改写成：

He may be late and in that case we ought to wait for him