考博英语复习：定语从句还可以这样“变形”？

最近在辅导过程中，有学员提出一个非常有“价值”的问题，我忍不住要做个分享。先来看看学员提出的问题，大家也先思考思考。

问题：以下句子中，in which 是定语从句吗？如果是，这个从句怎么不是句子结构呢？ 

The best box (hard-sided or soft) has an insulated lining and a pocket in which to place a thin freezer pack to help keep the contents cold until they are consumed.

这个句子的大意是：最好的盒子（硬边或软边）有一个绝缘衬里和一个口袋，里面放一个薄的冷冻包装，以帮助保持里面的东西在食用之前保持低温。从结构和逻辑上看，in which to place a thin freezer pack to help keep the contents cold until they are consumed这部分是作为定语修饰a pocket。

下面来回答上面提出的这个问题。“介词 + which/whom”除了用于引导定语从句外，还可以用于引导动词不定式短语，即“介词 + which/whom + 动词不定式”。这一结构可以理解为定语从句的一种简化形式，在句中做定语，修饰前面的名词。其实，也是不定式做定语的一种用法。例如：

1. There are enough chairs for the guests on which they can sit. （有足够的椅子供客人坐。）

可以简化为：There are enough chairs for the guests on which to sit.

2. People with whom you will cooperate are capable. （与你合作的人都是有能力的。）

可以简化为：People with whom to cooperate are capable.

3. His dream was to have his own shop in which he can produce the workings of his own hands. （他的梦想是拥有自己的店铺，自己动手制作作品。）

可以简化为：His dream was to have his own shop in which to produce the workings of his own hands.

4. Like birds they have a single opening with which they produce eggs, have sex and expel waste.（像鸟类一样，它们只有一个开口，用来产卵、交配和排泄废物。）

可以简化为：Like birds they have a single opening with which to produce eggs, have sex and expel waste.

5. You should first find a room in which we can put the things. （你应该先找一个放东西的房间。）

可以简化为：You should first find a room in which to put the things.

6. There was insufficient evidence on which we can base a change of decision.（没有足够的证据可以作为改变决定的依据。）

可以简化为：There was insufficient evidence on which to base a change of decision.

当然，并不是所有这种情况可以这样简化转换，例如：On some level, forgetfulness would ease the grievousness of this psychological dynamic with which they are tormented.（在某种程度上，遗忘可以缓解这种他们饱受折磨的心理变化所带来的痛苦。）此句则转换不了，若是生硬转换：On some level, forgetfulness would ease the grievousness of this psychological dynamic with which to be tormented.就会产生表达不清楚的情况，无法表达谁备受折磨。

因此，是否进行转换简化还得根据具体情况而定，必须确保意义表达清楚无歧义。

考博英语语法复习参考资料《华慧考博英语语法基础提升及长难句突破》。