The gang was sentenced to ten years in prison for planning a bank-robbery.

bank-robbery 是由 bank（银行）和 robbery（抢劫）组成的复合名词，中间用连字符连接。bank 指金融机构，robbery 指非法夺取他人财物的行为。 bank-robbery 指"银行抢劫"，即通过暴力或威胁手段非法夺取银行资金的行为。