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crossing (shares)
知人のばいかいで良い物件を紹介された。
Through an acquaintance's mediation, I was introduced to a good property.
彼がばいかいとなって二人を引き合わせた。
He served as a go-between and introduced the two.
蚊がばいかいとなって病気が広がった。
The disease spread with mosquitoes serving as carriers.