紧缩定语从句就是指把一个定语从句紧缩成“ 介词+关系代词+不定式”结构。这类结构主要用于正式文体中。

She must have time in which she can grow calm.=She must have time in which to grow calm.

她必须有冷静下来时的时间。

Allow me one minute in which I can change my clothes. =Allow me one minute in which to change my clothes.

给我一点时间换衣服

He was miserable unless he had neighbors with whom he could quarrel.=He was miserable unless he had neighbors with whom to quarrel.

他要是没有邻居吵架就难受。

若语义清楚，且结构恰当，“介词+关系代词+不定式”结构有时可进一步将其中的关系代词省略，而只保留介词和不定式（介词要移至不定式之后，且当先行词为表时间的名词时，该介词通常省略）

She must have time to grow calm (in).

她必须有冷静下来时的时间。

Allow me one minute to change my clothes (in).

给我一点时间换衣服。

He was miserable unless he had neighbors to quarrel with.

他要是没有邻居吵架就难受。