网友的问题逐个解答如下：

13. The young couple need a lot of money with which to buy a new house.

这里with是介词，介词后面加名词/代词/doing。为什么可以加which to buy还是with which然后to buy a new house修饰名词？with…结构这里是作状语修饰need吗，如何翻译。

——with which to buy a new house，是省略式定语从句

在含将来意义的定语从句中，我们可以省略主语和谓语的一部分（主要是情态动词和助动词），而代之以“介词+关系代词+不定式”的形式，叫做省略式定语从句。

I have saved a sum of money with which to buy a new car for myself.

我已经攒了一笔钱，要用这些钱为自己买一辆新车。

本句的完整形式为：I have saved a sum of money with which I’ll buy a new car for myself.

I was trying to find a place in which to lay the new piano.

我在试图找一个能放这台新钢琴的地方。

本句的完整形式为：I was trying to find a place in which I could lay the new piano.

【特别注意】

1. 在这类句子里，主句的主语必须与不定式的逻辑主语一致，否则不可改为省略式定语从句。试比较：

I was trying to find a place in which to live.我在设法找一个我可以住的地方。

I was trying to find a place in which my younger brother could live. 我在设法找一个我弟弟可以住的地方。

2. 不定式与现在分词作结果状语的区别

    不定式作结果状语多表示出乎意料的结果，此时不定式前可加上only以示强调，还常见于too...to,enough...to句式中；而现在分词作结果状语主要表示一种顺其自然的结果（即前面是后面的原因）。

    I woke up in the morning, (only)to find the outside world greatly changed.

    我早晨醒来，发现外面的世界变了。（出乎意料的结果）

    The heavy rain lasted a week, flooding two-thirds of the land.

    大雨下了一个星期，淹没了三分之二的田地。（顺其自然的结果）

14. Tom took a taxi to the airport,only finding his plane high up in the sky.

其中high是宾补,up是副词修饰high,in the sky是修饰up吗？high up in the plane怎么分析。一般碰到这种一大串介词副词混在一起的怎么办呢。谁修饰谁呢。

——此句有错误。改为：Tom took a taxi to the airport, only to find his plane high up in the sky.

表示出人意料的结果，使用不定式，不能用现在分词。而且不定式前常加上only。

    She hurried to the station only to be told the train had gone. 她匆忙赶到车站却被告知火车已走了。

find his plane high up in the sky 的结构：

find（动词） his plane （宾语）high （形容词作宾补）up （副词小品词作状语）in the sky（介词短语作状语）

15. There are few teaching positions left in big cities,and at he same time there are shortages of teachers in small towns.

Left修饰positions，in big cities是作状语修饰left还是positions或者修饰there be?应该怎么翻译。同样in small towns是修饰teachers还是shortages?

—— left in big cities 过去分词短语作定语修饰positions；而in big cities 是 left 的地点状语。left“余下的；现有的”。 in small towns 是there be 存在句的地点状语，当然修饰be动词，不可能是定语。

16. It’s just a short distance from here to the restaurant.

其中from here to the restaurant是状语吗修饰系表结构，还是修饰distance的定语。这里It代表什么呢？含义是什么？

——from here to the restaurant 是介词短语作状语，具体说是地点状语。it 是代词，可以指代“时间、天气、距离等”。