aritcle 一問

訓豬：
首先你要明白每個冠詞(Article), 不論是a, an, the 等在文法上是一個指示形容詞( Demonstative Adjective)。
在 I went to the hospital to visit my aunt who had been admitted for acute
appendicitis. 這句子中hospital 前加 the 的必要 是指明某一所醫院,是aunt因急性盲腸炎進入的那所醫院, 不是其他任何一所醫院。

在As Rita was walking along the street on her way to school, she saw a
one-thousand dollar note lying on the pavement.這句子中的school 已帶有
the school in which she studies 的意識, 所以習慣上在這類慣常的生活用語中把 the 删掉(understood 或 omitted)了去, 免令句子累贅。但當然如該學校
並非Rita所就讀的學校,如句子是Rita was wlking along the street on her way
to the school for an interview, she saw a one-thousand dollar note lying on
the pavement.在這情形下school 之前便要加 the 去指出那並不是Rita 正在
就讀的學校。

所以要留意很多生活上常用到的句子中, 但凡在短語(Phrase)的受詞(Object)
前有一個介系詞(Preposition)時, 在文法上也要把冠詞(Article)删去(omitted
或understood)了的,如以下所舉例：
at home, at daybreak, at school, to school, at noon, by bus, at sunrise,
on demand, on foot, in jail, at ease, under ground, on earth, by land等等。

2010-10-02 13:49:10 補充：
對不起,在參考資料欄內把 grammar一字 錯打為grammer, 特此更正, 並希原諒。

因為這是慣用法 :)

很久很久以前，一個城市通常都只會有一所醫院、警察局、消防局、機場、火車站，所以用這些詞語時，在泛稱時都會用the。

"to school" 也是一個固定用法，在非指名學校時不可以加article.
I go to school every weekday.
He took bus #3 to school.

第一句子, 是指示某間 hospital, 雖然沒有提到醫院名稱, 因為你不是去任何一間醫院.
所以使用definite article, "the"..

Go to hospital if the pain gets worse. (不用 the) 

第二句子, 不用加 the, to school 是指返學, 重點不是某間學校, 尤其是學校建築物.

I left school long time ago. (這離開是解畢業或停學, 不是指學校建築物)
He left the school at 3:00 p.m. yesterday. (是指學校建築物)

Warning: American English 沒有 British English 分開這麼清楚.

Go to the hospital if the pain gets worse. (American English)

She came out of hospital last month. (British English)
She came out of the hospital last month. (American English)