介词用“as”表示“作为”的意思。

全局意思是：我给妈妈花儿作为礼物。例句：My dad bought me a new laptop as a reward for my passing the CET-6.我爸爸给我买了一台因电脑作为通过大学英语六级考试的奖励。Bill and Nick were asked to pay for 500 dollars as punishment. 比尔和尼克被要求罚款500美元作为惩罚。