介 系 詞 是 解 甚 麼?

介詞的正確英文字是 Preposition.
多用於名詞或代名詞前,表示處所、位置、時間、
方法...等。常用的 preposition 有
in, on, into, onto, up, from, to , out of, on behalf of,
in front of, over, under, about, above, across, after,
against, along, among, around, at, before, behind,
below, beneath, beside, between, beyond, by, despite,
down, during, except, for, inside, near, off, out, outside,
past, since, through, throughout, till, toward, underneath,
until, up, upon, with, within, and without.

A preposition links nouns, pronouns and phrases to other words in a sentence. The word or phrase that the preposition introduces is called the object of the preposition.
A preposition usually indicates the temporal, spatial or logical relationship of its object to the rest of the sentence as in the following examples:
以下的句子 說出書本的位置。

The book is on the table. (上面)
The book is under the table. (下面)

以下表示「她在課堂上看書」
She read the book during class.

網上有很多資料入 yahoo 搜尋吧！
http://www.uottawa.ca/academic/arts/writcent/hypergrammar/preposit.html

http://grammar.ccc.commnet.edu/grammar/prepositions.htm
(1) use at to designate specific times.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
I usually sleep at 11:15 p.m.
(2) use on to designate days and dates.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
Peter is coming on Monday.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
We shall have a party on the first of June.
(3) use in for nonspecific times during a day,
a month, a season, or a year.


圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
She likes to swim in the morning.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
It's too hot in summer .

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
He was born in 1971.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
He will go to England in August.

在英文十類單詞中，介詞 Preposition 是其中一類。
什麼是介詞？介詞不能單獨使用，一定要與名詞或代名詞一起
以構成介詞短語，當作形容詞、副詞或名詞來使用。
介詞 + 名詞 / 代名詞 = 介詞短語 Prepositional Phrase
什麼是短語？短語是不含主語和謂語動詞的詞組。
當短語當作形容詞來用時，稱為「形容詞短語」Adjective Phrase。
當短語當作副詞來用時，稱為「副詞短語」Adverb Phrase。
當短語當作名詞來用時，稱為「名詞短語」Noun Phrase。