earth的關代要用where還是which?

1.介繫詞加上關係代名詞表示原因、地方、方法與時間時，可以關係副詞why、where、how、when來代用。空格處應該是on which，可以 where代用。
2.on which、 where、that 都可使用：
The earth which we live on is a beautiful planet.
=The earth on which we live is a beautiful planet.
=The earth where we live is a beautiful planet.
=The earth that we live is a beautiful planet.
=The earth we live on is a beautiful planet.
***********




2011-11-21 09:36:47 補充：
The earth that we live is a beautiful planet.請修正為The earth that we live on is a beautiful planet.謝謝大家的指導-----

為了讓您清楚些及一勞永逸，請容我離題一下:
疑問詞:what/which/who/when/where/why/how可分為
疑問代名詞:what/which/who
疑問副詞: when/where/why/how 把以上換個身分可成如下:
關係詞:what/which/who/when/where/why/how可分為
關係代名詞:what/which/who
關係副詞:when/where/why/how
請記住副詞不可當主詞或受詞。在解釋您的問題前請熟悉下列替換
介係詞+which=when/where/why 故您的例句可寫成
The earth where we live is a beautiful planet.
=The earth (which) we live on is a beautiful planet.
=The earth on which we live is a beautiful planet.
關代當受詞可省略，但在介詞後的關代則不可如最後一句 。底下是
判斷關代是主詞或受詞的簡易方法:
先行詞+關代+動詞.........此關代為主詞不可省略但可刪減(有緣再解說
如何刪減)
The girl who has big eyes can run fast.
I know the girl who has big eyes.
先行詞+關代+主詞+動詞.....此關代可省略，要注意的是，當受詞的關代
必須符合兩條件之一及當形容詞(關係)子句
中的及物動詞或介詞的受詞例:
The girl (who) I know has big eyes. 關代當know的受詞，可省略
The girl (who) I am talking about has big eyes. 關代當about的受詞，可省略
The girl about whom I am talking has big eyes. 同上，但在介詞後不可省略
[我的部落格有:英文文法 , 英文的學習心得, 英檢的實戰傳授, 英檢初、中級文法題庫可練功 和解惑及一些思考小品。 歡迎來逛逛(http://tw.myblog.yahoo.com/locamel124538)]






2011-11-21 01:08:02 補充：
我是單指神功，在回答您問題時是第一位，弄好解答已成第二了，我前面的大大給的答案也是正確的，除了倒數第二題他遺漏了live 後的on 正確的句子是
The earth that we live on is a beautiful planet. that當on的受詞是可省略的，請查照。

The earth which we live on is a beautiful planet.
The earth that we live on is a beautiful planet.