How to use 紹介される?

Question

Active

A: AはBにCを紹介する。

A': A introduces C to B.

Questions

How to make C and B (respectively) subjects of passive sentences?

Answer 1

"～によって" can be used when ～に is already consumed by the main verb.

• Cは（Aによって）Bに紹介される。
• Bは（Aによって）Cを紹介される。
• Bは（Aに）Cを紹介される。

Note that CはBに紹介される can be ambiguous ("C was introduced by B to someone" vs "C was introduced to B by someone"). 彼に紹介されたレストラン would almost always mean "the restaurant introduced by him." 彼に紹介された人 usually means "a person introduced by him" but may mean "a person introduced to him," depending on the context.