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to call out to; to hail; to address
to appeal (e.g. to the public); to urge; to exhort; to advise
市長が市民にボランティアへの参加を呼びかけた。
The mayor called on citizens to participate in volunteer activities.
駅前で署名活動をして通行人に呼びかけてみた。
I collected signatures in front of the station and appealed to passersby.
先生が生徒たちに静かにするよう呼びかけている。
The teacher is calling on the students to be quiet.