6种与when（这时「突然」）搭配的结构
作为“这时（突然）”含义的when前面的分句可以是过去进行时、过去完成时等，
孺人常见的还有be about to do, be on the point of doing, be in the acting of等结构。
be (just) doing sth + when
智力题be (just) about to do sth + when
be on the point of doing sth + when
be in the act of doing sth + when
had just done sth + when
had hardly/barely/scarcely done sth + when /before …did
赠刘景文was/were (just) doing…when
《COBUILD英汉双解词典》第2227页when词条3.1
房屋买卖协议书when（表示发生了某事，从而打断了原来计划或需要做的事，通常前一个分句中用just或about to）（可是）这时
I was just going out whenthere was a knock at the door.
我刚要出去，可是这时有人敲门。
be on the point of (doing) sth…when
《COBUILD英汉双解词典》第1484页point词条17.5
on the point of (doing) sth即将…之时，正要…的时候
As they were on the point of tting out, a light rain began to fall.
当他们就要出发的时候，外面下起了小雨。
《朗文当代高级英语辞典》第五版第1925页point词条
I was on the point of giving up the arch when something caught my eye in the bushes.
我正要放弃搜索时突然注意到灌木丛中有什么东西。
《韦氏高阶英汉双解词典》第1594页point词条
The police are on the point of solving the ca.
(= the police have almost solved the ca) 警方就要破案了。
《剑桥高阶英汉双解词典》第1676页point词条
be on the point of (doing) sth即将…之时，正要…之时
As we were on the point of giving up hope, a letter arrived.
正当我们要放弃希望之时，来了一封信。
She was so tired that she was on the point of collap. 她累得要垮掉了。
be about to do …when
《COBUILD英汉双解词典》第2227页when词条3.1
when（表示发生了某事，从而打断了原来计划或需要做的事，通常前一个分句中用just或about to）（可是）这时
I was about to go to bed when I heard cars purr in the distance.
我正要上床，但这时听到了远处有汽车呜呜作声。
《COBUILD英汉双解词典》第5页about词条
be about to do sth即将
Her father is about to retire. 她父亲即将退休。
He was just about to go on stage again. 他即将再度登台。
《COBUILD英汉双解词典》第1054页just词条
just行将；即将；刚要（与进行时态动词以及about to, going to等连用）
I’m just coming. 我就来。
I’m just making us some coffee, Chris. 我正要给我们煮点咖啡，克里斯。
They were just about to leave when there was a knock on the door.
他们刚要离开，响起来敲门声。
be in the act of (doing) sth when
太仓沙溪古镇
《柯林斯高阶英汉双解学习词典》第27页act词条
in the act of doing sth正在做…
Ken was in the act of paying his bill when Neil came up behind him.
当尼尔从后面走过来时，肯正在付账。
《韦氏高阶英汉双解词典》第20页act词条
in the act (of doing something): while doing something正在（做某事）当场
When they arrived, I was just in the act of startingto make dinner.
他们到的时候我正要开始做晚饭。
had (just) done sth when
《COBUILD英汉双解词典》第1750页cond词条
He had just finished his cond cup of coffee when the phone rang.
电话铃响时他刚喝完第二杯咖啡。
波立维是什么药
《COBUILD英汉双解词典》第2227页when词条
when（表示发生了某事，从而打断了原来计划或需要做的事，通常前一个分句中用just或about to）（可是）这时
We hadn’t gone ten minutes whenSam decided he wanted to go home.
我们走了还不到10英里，可这时萨姆决定要回家了。
【注意】
hardly/ barely/ scarcely…when/before的结构中，若hardly/barely/scarcely置于句首，主句（而非when/before之后的从句）需要使用部分倒装的结构。
目前高考英语所考察的是这个结构主句使用过去完成时，而后when/before引导的从句使用一般过去时态。
hardly…when
《朗文当代高级英语辞典》第五版第1149页hardly词条3
hardly…when/ before
She had hardly sat down when the phone rang. 她刚坐下电话就响了。
应用密码表示一件事紧跟另一件事，一般用had hardly或had scarcely：
I had hardly got in the hou when the phone rang. 我刚进屋电话就响了。
在文学作品中，可以将hardly获scarcely置于句首，后接had和主语：
Hardly had I got in the hou when the phone rang. 我刚进屋电话就响了。
《柯林斯高级英语用法词典》第377页hardly
hardly有时用在较长的句子结构中，表示“刚……就”。
The local police had hardly finished their examination when the CID arrived.
当地警察刚刚检查完，刑事调查部的人就到了。
在这样的句子中，要用when，而不用than。
barely…when
《朗文当代高级英语辞典》第五版第170页barely词条3
贴门神
barely: ud to emphasize that something happens immediately after a previous action刚刚（表示强调）= only just（英）
Graham had barely finished coffee when Henry returned.
格雷厄姆刚刚喝完咖啡，亨利就回来了。
《柯林斯高阶英汉双解学习词典》第189页barely词条2
If you say that one thing had barely happened when something el happened, you mean that the first event was followed immediately by the cond刚刚…（就）
