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to mix; to combine; to include
to exchange (words, fire, etc.)
to cross (e.g. swords); to join together
彼女はいくつかの冗談を話に交えた。
She mixed a few jokes into the conversation.
様々な意見を交えて活発な議論が行われた。
A lively discussion was held with various opinions included.
彼はユーモアを随所に交えている。
He is weaving humor throughout his speech.