Colocación de preposiciones en oraciones de relativo

A menudo, las oraciones de relativo contienen preposiciones y un pronombre relativo que es el objeto de la preposición. En el inglés de uso cotidiano la preposición suele colocarse al final de la oración de relativo y el pronombre puede incluirse u omitirse. En inglés formal la preposición antecede al pronombre relativo y, en este caso, tal pronombre no puede omitirse. En los ejemplos que figuran a continuación, los pronombres que van entre paréntesis pueden omitirse.

Ejemplos
Inglés cotidiano Inglés formal
Is that the man (who) she arrived with? Is that the man with whom she arrived?
Does he know the girl (that) John is talking to? Does he know the girl to whom John is talking?
The person (who) he is negotiating with is the Chairman of a large company. The person with whom he is negotiating is the Chairman of a large company.
It is a club (which) many important people belong to. It is a club to which many important people belong.
He liked the people (that) he lived with. He liked the people with whom he lived.
The tree (that) they had their picnic under was the largest and oldest in the park. The tree under which they had their picnic was the largest and oldest in the park.
It was the river (that) the children preferred to swim in. It was the river in which the children preferred to swim.
The jungle (that) the tribe lived in was full of strange and unusual animals. The jungle in which the tribe lived was full of strange and unusual animals.