She must have time in which she can grow calm.
=She must have time in which to grow calm.
Allow me one minute in which I can change my clothes.
=Allow me one minute in which to change my clothes.
He was miserable unless he had neighbors with whom he could quarrel.
=He was miserable unless he had neighbors with whom to quarrel.
She had some money in the bank, with which she could help her mother.
=She had some money in the bank, with which to help her mother.
She must have time to grow calm (in).
Allow me one minute to change my clothes (in).
He was miserable unless he had neighbors to quarrel with.
It’s reported that the city needs more land to build houses on.
正：Have you ever spoken to the man who lives next door?
误：Have you ever spoken to the man who to live next door?
正：There the children had a garden in which they could play. (定语从句)正：There the children had a garden in which to play. (紧缩定语从句)正：There the children had a garden to play in. (不定式作定语)误：There the children had a garden which to play in.(不能将介词置于不定式之后)