against是什么词性？如何使⽤？
介词against的⽤法
要特别注意against是介词，不是动词，可表⽰多种含义，其⽤法如下：1)表⽰“反对”、“违背”之意。如：
①They are strongly against the idea. 他们强烈反对这个意见。
②Are you for or against my plan? 对于我的计划你是赞成还是反对？③What have you done is against the law.你所做的事情是违法的。
④Jane married Jack against her own will.简与杰克结婚，违背了⾃⼰的意愿。2)表⽰“撞击”、“碰着”之意。如：
①The rain was beating the windows. ⾬点拍打着窗户。
②Tom hit his head against a tree in the dark.⿊暗中汤姆的头撞在⼀棵树上。3)表⽰“倚在”、“紧靠”之意。如：
①Place the ladder against the wall.把梯⼦靠在墙上。4)表⽰“逆着”的意思。如：
①We are sailing against the wind.(with the wind表⽰“顺风”)我们的船正在逆风⾏驶。5)表⽰“衬托”、“相映”、“对照”之意。如：
①Red flags stand out brightly against the blue sky.红旗在蓝天的衬托下显得分外鲜艳。6)表⽰“防备”、“预防”之意。如：
①People are warned against pick-pockets. ⼈们得到告诫，要谨防扒⼿。
