upon doing的用法

"Upon/on doing" 表示在某些动作或事件发生之后，接着会发生另外一件事情。例如：- Upon finishing his homework, he watched TV.（他做完作业后，就看电视了。）- On hearing the news, she burst into tears.（听到消息后，她哭了起来。）

upon doing的用法

on/upon （doing） sth. 表示“一……就……”。如：

On（my） asking for information I was told I must wait.

我一打听情况，就被告之等着。

On his return from Canada, he set to work. 他一从加拿大回来就开始工作。 

“一……就”的其他表达方法：as soon as, the moment/minute, immediately, hardly … when, no sooner … than等。

upon doing和once doing和when doing的区别

1、on /upon doing sth

刚一做某事（就）

结构：介词+动名词

功能：相当于as soon as引导的时间状语从句。

例如：On arriving home I discovered they had gone.

我一到家就发现他们已经离开了。

= As soon as I arrived home，I discovered they had gone.

= On my arrival home I discovered they had gone. （ on/upon doing必须注意，后面句子主语就是前面doing 动作的发出者。）

On arriving at the village,these college students went to help the farmers with their work.

=As soon as they arrived at the village,these college students went to help the farmers with their work. 这些大学生一到村里就去帮助农民工作。

= On their arrival at the village,these college students went to help the farmers with their work. （ on/upon doing必须注意，后面句子主语就是前面doing 动作的发出者。）

Upon going out of the room,Jack heard his cellphone ringing.

=As soon as he went out of the room,Jack heard his cellphone ringing.（ on/upon doing必须注意，后面句子主语就是前面doing 动作的发出者。）

杰克一走出房间，就听到他的手机响了。

2、once doing

一旦做某事

结构：连词once +加动名词，可以看作是once 条件状语从句的省略

功能：相当于once 引导的条件状语从句

例如：

Once trying them on, You can't return underwears.=

You can't return underwears once you've tried them on.

=Once you've tried them on, you can't return underwears.

内衣一旦试穿后就不能退。（once doing sth，必须注意，后面句子主语就是前面doing 动作的发出者）

Once making a promise,you should try your best to fulfil it.

=Once you have made a promise,you should try your best to fulfil it.

一旦做出承诺，你就应该尽力履行。（once doing sth，必须注意，后面句子主语就是前面doing 动作的发出者）

特别注意：后面句子主语与once 后面的动词动作是被动关系时，经常使用过去分词。

例如：

Once bitten,twice shy. 一朝被蛇咬，十年怕草绳。

Once created, LUNs need to be assigned to hosts.

=Once LUNs are created, they need to be assigned to hosts.

LUN一旦创建，就必须被分配到主机。

3、when doing sth 是省略形式的状语从句，分词的逻辑主语是主句的主语，表示“当……时”，有时候也可表“一……就……”的意义。

如：When staying at home, I often play chess with my grandpa. 在家时，我常和爷爷下棋。（When staying at home = When I stay at home）

When seeing her mother, the little girl dropped her toy and rushed to her. 一看到妈妈，小姑娘就丢下玩具向她跑去。（When seeing her mother = When / As soon as she saw her mother = On seeing her mother）

介词upon的用法

1、作状语

The decision was based upon two considerations.

这一决定基于两种考虑。

He set the tray upon the table.

他把盘子放在桌子上。

He bent forward and laid a kiss softly upon her forhead.

他弯腰向前，在她额头上轻轻一吻。

2、作表语

The summer season was almost upon them again.

转眼间他们又要过夏天了。

The long -threatened storm was upon us.

酝酿多时的暴风雨就要向我们袭来。

3、作定语

Row upon row of women surged forwards.

一排一排的女人涌向前去。

包含on的动介短语，有时候可以把on换成upon.

act on… 遵照……行事

agree on… 就……达成一致

call on… 访问，号召

catch on 理解

center on… 关注

comment on… 评论

concentrate on… 关注

count on… 依靠

depend on… 依靠

rely on… 依靠

draw on… 依靠

feed on… 以……为主食

live on… 以……为主食

fit on… 试穿

focus on… 关注

get on… 上车

hit on… 忽然想起

improve on… 改善

insist on… 坚持

keep on… 坚持

knock on… 敲

lean on… 靠着

reflect on… 回顾

take on… 雇佣，负责任，

呈现，竞争

try on… 试穿

wait on… 伺候