my sister bought a dress for me改为同义句
my sister bought a dress for me同义句为：My sister bought me a dress .
原句句意：我姐姐给我买了一个裙子。buy sb sth = buy sth for sb为某人买某物，故同义句为My sister bought me a dress.
buy的用法：
用法1: buy的基本意思是用金钱换取等价物，即“购买”，是普通用词，可接具体物品如书籍、衣物等作宾语。
用法2: buy在句中主要用作及物动词,偶尔用作不及物动词。用作及物动词时,后接名词或代词作宾语，有时还可接双宾语，其间接宾语可转化为介词for的宾语。可用于被动结构。
用法3: buy的主语—般是人，也可以是无生命的事物。
用法4：表示“在某商店买”可接介词at；表示“从某处买”可接介词from，of,，off；表示“花多少钱买”可接介词for，at；表示“给某人买”可说buy sb sth，也可说buy sth for sb，不能说buy sthto sb。
用法5: buy是非延续性动词，不可与表示时间段的状语连用，但可与表示时间点的状语连用。
双语例句：
1. Somehow, he'd managed to persuade Kay to buy one for him.
不知用了什么方法，他成功说服凯给他买了一个。
2.l might buy one for a friend's birthday as a giggle.
我可能会买—件送给朋友当生日礼物，逗他开心。
3. Who wants to buy a computer from a failing company?
谁愿意从—家要倒闭的公司买计算机呢？
4. Show me which one you like and l'll buy it for you.
指给我看你喜欢哪个，我给你买。
5.You can buy a formulation containing royal jelly, pollen and vitamin C.
可以买—种含蜂王浆、花粉和维生素C的配方产品。
6. They used to buy ten kilos of beef in one lump.
他们过去常买10公斤重的整块牛肉。
7.Ford had the bright idea of paying workers enough to buy cars.
福特公司想出了—绝妙的主意:付给工人足够的薪水去购买汽车。
8.They had to buy everything at inflated prices at the ranch store.
他们不得不在农场商店以高价购买所有东西。
9. Shopkeepers buy them in bulk and resell them for 150 each.
店主们先大量购进，然后再以150英镑的单价将它们转卖出去。
