關代which的用法

Less than 3 percent of the world's water is fresh, and most of it is trapped in polar ice or buried undergrounded in springs too deep to reach.解析:1. 兩個句子中間已經有連接詞and, 所以關係代名詞不適用. 用一般的 it (複數用them) 就可以.2. 假如題目中的and 拿掉, 改成Less than 3 percent of the world's water is fresh, most of which is trapped in polar ice or buried undergrounded in springs too deep to reach.就要用關係代名詞which非限定的用法, 補充說明.

2013-12-25 22:25:47 補充：
關係代名詞有限定和非限定的用法. 非限定的用法就是要在前面加上一個逗號, 它的作用並不是拿來限定先行詞的範圍, 而是用作補充說明之用.
Prices on the stock market, which have been static, are now rising again.
Most feed entirely on plants, which makes them bothersome.

2013-12-25 22:29:13 補充：
There must be something wrong with my left arm, which is asleep.
Best buys of the week are carrots, which are plentiful and cheap.
His jokes didn't even raise a smile, which was embarrassing.
以上是我網路上找的例句, 你可以參考一下.
在你的句子中, most of which 是關係代名詞的主格形式,

2013-12-25 22:32:59 補充：
跟Best buys of the week are carrots, which are plentiful and cheap.這句比較像.
像這種非限定的用法, 有些可以直接改寫成用 連接詞 and 的句子:
Best buys of the week are carrots and they are plentiful and cheap.
His jokes didn't even raise a smile and that was embarrassing.

2013-12-25 22:35:31 補充：
當你的句子本身已經有and當作連接詞的時候, 後面的句子再度提到前面講過的名詞時, 只要簡單的用一般的代名詞, it/them/he/she/him/her/.....就可以了.