against

紧贴、倚靠

She leant her spade against the tree while she rested. （她休息时，把铁锹靠在了树旁。）

To do the wall sit, squat with your back against the wall and heels on the ground. （做靠墙静蹲这个动作时，你需要背靠墙壁半蹲，脚后跟踩在地面上。）

逆着、迎着……的方向，与……的方向相反

Salmon swim against the current to return to their birth stream so they can breed there. （鲑鱼逆流而上，游回到出生时所在的溪流，从而在那里繁殖。）

The ship has to sail against the wind to reach the port. （这条船必须逆风航行才能到达港口。）

反对某个观点、计划或活动，持相反意见

I’ve heard you want to know what people think about the idea of prolonging the meetings. Well, I’m against it. （听说你想知道大家对延长会议时间这件事情的看法。我是反对的。）

Normally, I’m very much against kids eating too many sweets. But I’ll make an exception today because it’s my son’s birthday. （我通常很反对孩子吃太多甜食。但我今天会破个例，因为是我儿子的生日。）

以防，防止，防备

A healthy diet might protect you against a number of diseases. （健康的饮食也许能保护你免受多种疾病的侵害。）

My bike was stolen yesterday! It’s good that I had already insured it against theft. （我的自行车昨天被偷了！幸好我早就给它上了防盗保险。）

对阵，对抗

Who is our favourite football team playing against tomorrow? （咱们最喜欢的足球队明天要和哪支队伍比赛？）

I just played a game of Go against my dad and I won! （我刚和我爸下了一盘围棋，我赢了！）

某个事物以……为衬托

These peach blossoms look so beautiful against the blue sky. （这些桃花在蓝天的映衬下是如此美丽。）