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.