I am going to buy a gift for her.

for her 是状语？定语？间接宾语？

同意刘老师和曹老师解答，以上for +her 为介词+宾格代词构成介词短语，作状语成分。介词短语不具备名词语法功能，因此不能作动词宾语。

双宾语及物动词有以下几种情况归纳如下

(1) 双宾语易位时需借助介词to的常用动词

　　award sb. sth. = award sth. to sb. 颁奖给某人

　　bring sb. sth. = bring sth. to sb. 把某物带给某人

　　hand sb. sth. =hand sth. to sb. 把某物递给某人

　　lend sb. sth. = lend sth. to sb. 把某物借给某人

　　mail sb. sth. = mail sth. to sb. 把某物寄给某人

　　offer sb. sth. = offer sth. to sb. 将某物给某人

　　owe sb. sth. = owe sth. to sb. 欠某人某物

　　pass sb. sth. = pass sth. to sb. 把某物递给某人

　　pay sb. sth. = pay sth. to sb. 付给某人某物（钱）

　　post sb. sth. = post sth. to sb. 把某物寄给某人

　　read sb. sth. = read sth. to sb. 把某物读给某人听

　　return sb. sth. = return sth. to sb. 把某物还给某人

　　send sb. sth. = send sth. to sb. 把某物送给某人

　　sell sb. sth. = sell sth. to sb. 把某物卖给某人

　　serve sb. sth. = serve sth. to sb. 拿某物招待某人

　　show sb. sth. = show sth. to sb. 拿某物给某人看

　　take sb. sth. = take sth. to sb. 把某物拿给某人

　　teach sb. sth. = teach sth. to sb. 教某人某物

　　tell sb. sth. = tell sth. to sb. 告诉某人某情况

　throw sb. sth. = throw sth. to sb. 把某物扔给某人

　　write sb. sth. = write sth. to sb. 给某人写信

　(2) 双宾语易位时需借助介词for的常用动词

　　book sb. sth. = book sth. for sb. 为某人预定某物

　　buy sb. sth. = buy sth. for sb. 为某人买某物

　　choose sb. sth. = choose sth. for sb. 为某人选某物

　　cook sb. sth. = cook sth. for sb. 为某人煮某物

　　draw sb. sth. = draw sth. for sb. 为某人画某物

　　fetch sb. sth. = fetch sth. for sb. 为某人去取某物

　　find sb. sth. = find sth. for sb. 为某人找到某物

　　fix sb. sth. = fix sth. for sb. 为某人准备某物

　　get sb. sth. = get sth. for sb. 为某人拿来某物

　　make sb. sth. = make sth. for sb. 为某人做某物

　　order sb. sth. = order sth. for sb. 为某人订购某物

　　pick sb. sth. = pick sth. for sb. 为某人采摘某物

　　prepare sb. sth. = prepare sth. for sb. 为某人准备某物

　　save sb. sth. = save sth. for sb. 为某人留某物

　　sing sb. sth. = sing sth. for sb. 为某人唱某物（歌）

　　spare sb. sth. = spare sth. for sb. 为某人让出某物

steal sb. sth. = steal sth. for sb. 为某人偷某物

有的动词后接的双宾语易位时，既可用介词to引出间接宾语，也可用介词for引出间接宾语，含义相同，如bring，play等：

Bring me today’s paper. = Bring today’s paper to [for] me. 

把今天的报纸拿给我。

He played us the record he had just bought. 

= He played the record he had just bought for [to] us. 

他放了他刚买的唱片给我们听。

有的动词后接的双宾语易位时，即可用介词to引出间接宾语，也可用介词for引出间接宾语，含义不同，如leave等：

They left me no food. = They left no food for me. 

他们没给我留一点食物。

My uncle left me a large fortune. 

= My uncle left a large fortune to me.

我叔叔死后留下一大笔财产给我。

而有的动词后接双宾语时，既不能用介词to引出间接宾语，也不能用介词for引出间接宾语，如allow, ask, cause, charge, cost, forgive, refuse等：

He allows his son too much money. 

他给他儿子的钱太多。

He asked me some questions. 

他问了我一些问题。

This caused me much trouble. 

着给我带来了许多麻烦。

He charged me five dollars for a cup of tea. 

他一杯茶向我要了5美元。

His mistake cost him his job. 

他的错误让他丢了工作。

I envy you your good luck. 

我羡慕你的好运。

They forgave him his rudeness. 

他们原谅了他的鲁莽。

He refused her nothing. 

她要什么就给什么