用不定式做狀語,表目的.
她這樣出丑實(shí)在是很不好.embarrass是個(gè)主動動詞,按著句意,她是被出丑,受尷尬,所以選B；另外embarrassed是形容詞,意思是尷尬.
關(guān)于不定式的用法很多,請參考：
1．作主語
作主語用的動詞不定式常常用it替代,動詞不定式（或短語）放在后面.例如：
It's easy to get lost in a big city like Tokyo．在東京這樣的大城市容易迷路.
It is terrible to see the ship sinking into the sea．目睹輪船沉入大海,真是太可怕了.
2．作賓語
Indians like to eat hot food．印度人喜歡吃辣味食品.
They need to look at a map．他們需要查看地圖.
有的動詞不定式在作帶有補(bǔ)足語的賓語時(shí),前面往往帶有形式賓語it.例如：
Do you think it necessary for us to learn to wait?你認(rèn)為學(xué)會等待對我們來說很必要嗎?
They improved the software to make it easier for people to use computers．他們改進(jìn)了軟件,使人們使用計(jì)算機(jī)更簡便了.
3．作表語
It seems to be an interesting book．它看起來是本有趣的書.
The old man's job is to take care of the flowers in the garden．這位老人的工作是照料花園里的花.
4．作賓語補(bǔ)足語
He told me not to bring you anything．他叫我不要給你帶任何東西.
Who taught you to play the music?誰教你彈這支曲子的?
5．作定語
動詞不定式作定語時(shí),要放在它所修飾的名詞或代詞后面.例如：
In my dreams I always have very difficult jobs to do．我在夢里總是做一些艱難的工作.
Every day he made one of the smaller animals bring him something to eat．他每天叫一個(gè)小動物給他帶來吃的東西.
6．作狀語
（1）表示目的
You can hide under my seat when the conductor comes to check the tickets．當(dāng)列車員來查票時(shí),你可以藏在我的座位下面.
In his third year,he left Harvard to work for a company called Microsoft．在三年級時(shí),他為了去微軟公司工作而離開了哈佛大學(xué).
（2）表示結(jié)果
動詞不定式作狀語表示結(jié)果時(shí)常與副詞too或enough連用.例如：
It's too heavy to carry．太重了搬不動.
The Californian ship arrived too late to save more people．加利福尼亞號來得太晚,沒能挽救更多的人.
7．和某些形容詞連用
和動詞不定式經(jīng)常連用的形容詞有sure,ready,happy,sorry,afraid等.例如：
He's very happy to see his wife．他見到妻子非常高興.
I'm sorry to trouble you．很抱歉打擾你了.
8．和疑問詞who,what,when,where,which,how構(gòu)成不定式短語作賓語.例如：
I don't know how to use a computer．我不知道怎樣使用計(jì)算機(jī).
Can you tell me when to start?你能告訴我什么時(shí)候出發(fā)嗎
1.不定式的被動態(tài)是由to be + -ed 分詞或to have been+ -ed分詞構(gòu)成.
2.不定式通常帶to ,但在某些搭配中不帶to ,在另一些搭配中既可帶to 也可以不帶to .例如：在would rather/would sooner/would(just)as soon,may/might(just) as well,cannot but/cannot help but等情態(tài)動詞之后不帶to .would rather/would sooner/would(just)as soon 之后也能跟than/as 分句,在這種分句中也不帶to.例如:I would just as soon stay as go.
3.如果except/but之前有動詞"do"的某種形式,其后通常用不帶to不定式（就是不帶to的意思）,否則帶to.
4.在Why.../Why not...句式中,也不帶to.
5.當(dāng)兩個(gè)帶to不定式由and或or連接是,第二個(gè)不定式符號?？墒÷?例如I intend to call on him and discuss this question again.但若兩個(gè)并列的帶 to不定式有對比含義,第二個(gè)不定式符號便不能省略 ：To be or not to be,that is the question.當(dāng)三個(gè)或三個(gè)以上帶 to不定式構(gòu)成排比結(jié)構(gòu)時(shí),所有的不定式符號均須保留：Read not to contradict or confute;nor to believe and take for granted;nor to find talk and discourse;but to weigh and consider.(Bacon)
這是我從別處轉(zhuǎn)來的,很詳細(xì),有時(shí)間的話lz可以看看.