并列句中的省略

1．并列句如果两个分句有重复处，后面部分就常常省略掉：
I work in a factory and my sister in a hospital．
我在工厂工作，我弟弟在医院工作。
My classroom is on the second floor and Tom's on the third．
我的教室在二楼，汤姆的教室在三楼。
He majors in finance，and I in international law．
他主修金融，而我主修国际法。
Someone has borrowed that book，but I don't remember who.
有人借走了那本书，但我不记得谁借的了。
The fox may grow gray，but never good．
狐狸会变老，却不会变好。(谚)

2．有时but，and等连词可引起一个短，有的词则省略了：
We tried to help him，but in vain．
我们想子帮助他，但没有用。
Newton did it and quite successfully too at the beginning．
牛顿这样做了，而且开头时还很成功。
There are still some errors in the program，and very serious ones too．
程序还有一些错误，而且是很严重的错误。
This happened and good thing too, as it helped us to realize our shortcomings．
发生了这事，也是好事，因为它帮助我们明白了我们的缺点。

3．另外，下面这些句子中也有词省略：
A little further and you will see a green mail box．
再往前走一点，你可以看到一个绿色的邮筒。(省略Go)
A few months more and the hydro-electric station would be providing power．
再过几个月水电站就要供电了。(省略Wait)
Well，another thing，have you sent out the invitation letter?
哦，还有一件事，邀请函发出去了吗?(I have to ask you)
Now，one more thing，I want to send a package by air mail．
还有一件，我寄一个航空包裹。(I have to do)