“This is a case where large interests are involved.” The preposition and relative will better express the meaning; as, “This is a case in which large interests are involved.”
The relative should be so placed as to prevent ambiguity, and as near as possible to its antecedent.
“Mr. Smith needs a surgeon, who has broken his arm.” Say, “Mr. Smith, who has broken,” etc.
“The figs were in small wooden boxes, which we ate.” “The figs which we ate,” etc.
“He needs no boots that cannot walk.” “He that cannot walk,” etc.
Omitted Relatives
The relative pronoun is often omitted when it should be expressed.
“The next falsehood he told was the worst of all.” Say, “The next falsehood that he told,” etc.
“It is little we know of the divine perfections.” Say, “Little that we know.”