??1996年1月的 CET-4的第45題是這樣的：
??I felt somewhat disappointed and was about to leave，______ something occurred which attracted my attention．
? A．unless????B．until??? C．when????D．while
? 本題從表面上看考核的是狀語從句中連詞的辨析，但其深層次上考查的卻是when的習慣用法中的一種情況：when引導的時間狀語從句，表達的意思是："突然，正當那時"。全句意思是："我覺得有些失望，正欲離開，突然發(fā)生了一件事吸引了我的注意力。?因此，本題答案C。
? 筆者在輔導四、六級考試時發(fā)現(xiàn)，歷年四、六級考試中when的習慣用法占有一席之地，為了使同學們進一步掌握when的習慣用法，下面筆者從四個方面，對when的習慣用法作以分析：
??1．主句中有過去進行時，be about to do sth．或go on doing sth．等時，從句中用 when，表達的意思是："突然，正當那時"。例如：
??I was picking cotton／I was about to go out／I had just stepped out of the door，when it started to pour．
??2．與hardly／scarcely．．．when剛……就 ?？嫉氖?BR> ??1）從句中的時態(tài)--過去完成時；
??2）hardly／scarcely放在句首，用倒裝語序。例如：
??Scarcely had he gone out when it began to rain heavily．
??3．when的省略
??1）在when連接的狀語從句中，常省略跟主句相同的主語和be動詞。其形式為： 連詞＋（主語＋be）＋分詞／名詞／介詞短語／形容詞。例如：
??When（you cross／you are crossing）the street，you should be careful．
??2）從句的主謂部分是it is／was（convenient，necessary，possible等）時，it is／was也經(jīng)常省略。例如：
??When（it is）necessary you can help us to do something．
??4．when it comes to．．．當提到…… When it comes to mathematics，I am completely at sea．
? 下面的試題摘自實考試題中，它們有的是顯形考題，有的是隱形考題，其中都涉及到了when的用法。同學們不妨試一試：
? 【真題聚焦】
??1．I had just started back for the house to change my clothes ______ I heard voices．?
??A．a(chǎn)s???? B．when?????C．a(chǎn)fter?????D．while?（1997／6／44B）
??2．The student was just about to ______ the question，when suddenly he found the answer．?
??A．a(chǎn)rrive at??B．submit to??C．work out??D．give up（1995／6／62D）
??3．I was halfway back to the cottage where my mother lived ______ Susan caught up with me．?
??A．when??B．while??C．until??D．though（2001／1／68A）
??4． ______ with the size of the whole earth，the highest mountain does not seem high at all．?
??A．When compared??B．Compare??C．While comparing??D．Comparing（1990／1／47A）
??5．We ______ our breakfast when an old man came to the door．??
??A．just have had??B．have just had??C．just had??D．had just had（1990／1／53D）
??6．I hope my teacher will take my recent illness into ______ when judging my examination．??
??A．regard??B．counting??C．a(chǎn)ccount??D．observation（1991／6／52C）
??7．Michael used to look hurt and surprised when ______ ．?
??A．scolding??B．to scold??C．having scolded??D．scolded（1995／1／58D）
??8．Doing your homework is a sure way to improve your test scores，and this is especially true ______ it comes to classroom tests．?
??A．when??B．since??C．before??D．a(chǎn)fter（1996／1／36A）
???????????????????????????????? 長春空軍第二航空學院/王志英
??I felt somewhat disappointed and was about to leave，______ something occurred which attracted my attention．
? A．unless????B．until??? C．when????D．while
? 本題從表面上看考核的是狀語從句中連詞的辨析，但其深層次上考查的卻是when的習慣用法中的一種情況：when引導的時間狀語從句，表達的意思是："突然，正當那時"。全句意思是："我覺得有些失望，正欲離開，突然發(fā)生了一件事吸引了我的注意力。?因此，本題答案C。
? 筆者在輔導四、六級考試時發(fā)現(xiàn)，歷年四、六級考試中when的習慣用法占有一席之地，為了使同學們進一步掌握when的習慣用法，下面筆者從四個方面，對when的習慣用法作以分析：
??1．主句中有過去進行時，be about to do sth．或go on doing sth．等時，從句中用 when，表達的意思是："突然，正當那時"。例如：
??I was picking cotton／I was about to go out／I had just stepped out of the door，when it started to pour．
??2．與hardly／scarcely．．．when剛……就 ?？嫉氖?BR> ??1）從句中的時態(tài)--過去完成時；
??2）hardly／scarcely放在句首，用倒裝語序。例如：
??Scarcely had he gone out when it began to rain heavily．
??3．when的省略
??1）在when連接的狀語從句中，常省略跟主句相同的主語和be動詞。其形式為： 連詞＋（主語＋be）＋分詞／名詞／介詞短語／形容詞。例如：
??When（you cross／you are crossing）the street，you should be careful．
??2）從句的主謂部分是it is／was（convenient，necessary，possible等）時，it is／was也經(jīng)常省略。例如：
??When（it is）necessary you can help us to do something．
??4．when it comes to．．．當提到…… When it comes to mathematics，I am completely at sea．
? 下面的試題摘自實考試題中，它們有的是顯形考題，有的是隱形考題，其中都涉及到了when的用法。同學們不妨試一試：
? 【真題聚焦】
??1．I had just started back for the house to change my clothes ______ I heard voices．?
??A．a(chǎn)s???? B．when?????C．a(chǎn)fter?????D．while?（1997／6／44B）
??2．The student was just about to ______ the question，when suddenly he found the answer．?
??A．a(chǎn)rrive at??B．submit to??C．work out??D．give up（1995／6／62D）
??3．I was halfway back to the cottage where my mother lived ______ Susan caught up with me．?
??A．when??B．while??C．until??D．though（2001／1／68A）
??4． ______ with the size of the whole earth，the highest mountain does not seem high at all．?
??A．When compared??B．Compare??C．While comparing??D．Comparing（1990／1／47A）
??5．We ______ our breakfast when an old man came to the door．??
??A．just have had??B．have just had??C．just had??D．had just had（1990／1／53D）
??6．I hope my teacher will take my recent illness into ______ when judging my examination．??
??A．regard??B．counting??C．a(chǎn)ccount??D．observation（1991／6／52C）
??7．Michael used to look hurt and surprised when ______ ．?
??A．scolding??B．to scold??C．having scolded??D．scolded（1995／1／58D）
??8．Doing your homework is a sure way to improve your test scores，and this is especially true ______ it comes to classroom tests．?
??A．when??B．since??C．before??D．a(chǎn)fter（1996／1／36A）
???????????????????????????????? 長春空軍第二航空學院/王志英