什麼情況之下可以略去"that"字?

我只是路過的人
我還是第一次見到這樣關於語法的對戰, 很有趣.

個人意見: 找不到raymond 錯了甚麼. 但開頭radioman 指raymond自已改了原本的句子, 這也是真的, 但raymond也只是試圖理解原句句意後作出修改使之符合語法, 這根本沒有甚麼可指摘的地方.

反觀radioman, 一開始便說人家是 "fake professional".

2011-05-23 01:01:59 補充：
我覺得回答了這個問題後便會捲入一場對壘中.

首先要說清楚一點, that 可以出現在名詞從句 (下面叫名詞性that-從句), 也可出現在關係從句. 這兩種都是subordinate clause:

A subordinate clause is a clause that is embedded as a constituent of a matrix sentence and that functions like a noun, adjective, or adverb in the resultant complex sentence.
(http://www.sil.org/linguistics/GlossaryOfLinguisticTerms/WhatIsASubordinateClause.htm)

簡單來說, 如果從句充當句子成分, 它就是subordinate clause

那麼, that字可否省略, 就分兩方面來說

A. that 在關係從句中作關係代詞的話,

如果這個關係代詞在從句中作動詞的賓語, 它就可以省略.
He loves the girl you love.如果這個關係代詞在從句中作介詞的賓語, 它就通常也可以省略.
He knows the girl we are talking about.
(在formal英語把介詞置於從句句首, 就不會用that, 只會用which/whom):
He knows the girl about whom we are talking.如果這個關係代詞在從句中作主語, 它就不可以省略.
He know that girl that loves me.Notes:
i) 這個關係代詞在主句matrix sentence中作何成分, 這與它可否省略是無關的. 只在乎它在從句中作何成分.
ii) 有些人會把省去的關係代詞that 叫做 zero relative pronoun, 記作Ø.

B. that在名詞性that-從句中作連詞
名詞性that-從句作主句的主語, 這個連詞不可省略.
That he is a liar is widely known.名詞性that-從句作主句的賓語, 這個連詞可省略.
字典在單及物動詞+finite that-clause 說"有時可省略",見P.1877; 但在雙及物動詞中的情況下沒有這項解說, P.1891.我自己認為名詞性that-從句作主句的賓語時, 不論是否雙及物動詞VP, 連詞that 全都是可省略的 (字典常說"有時可省略", 這是否因為字典作為工具書, 想寫得保守一點? 我認為是"總可省略", 雖沒有十足把握. 請賜教.)

另外, 我說"主句的賓語", 是指主句的動詞的賓語, 至於介詞的賓語, 我不清楚到底有沒有"介詞+名詞性that-從句"的例子.
? We are talking about that he is a liar.
(這句是我自己勉強造的句子, 不清楚是否正確, 請賜教.)

附1. 字典來源(見下圖)

附2. 兩類從句的分別
名詞性that-從句是整個句子(子句)當作一個名詞.
例如indirect speech 中, 由that引起的從句是動詞(reporting verbs)的一個賓語:
I didn't say that I was busy. / I didn't tell you that I was busy.
從句(除掉連詞後) I was busy 自己是完整的, that 只起連接作用.關係從句充當的角色是對名詞(詞組)作修飾/限定, 有人叫它做"定語從句", 受其修飾/限定的名詞叫做先行詞:
The stone that the builder has abandoned has become the chief cornerstone.
從句(除掉連詞後) the builder has abandoned 自己並未完整, 它仍欠了一個賓語. 連詞that 除起連接作用外, 還作代詞用, 代替從句的先行詞: the builder has abandoned the stone.


圖片參考：http://imgcld.yimg.com/8/n/HA00591740/o/701105220063413873442450.jpg

▲P. 1579

圖片參考：http://imgcld.yimg.com/8/n/HA00591740/o/701105220063413873442461.jpg

▲P. 1580

圖片參考：http://imgcld.yimg.com/8/n/HA00591740/o/701105220063413873442462.jpg

▲P. 1877

圖片參考：http://imgcld.yimg.com/8/n/HA00591740/o/701105220063413873442473.jpg

▲P. 1891

圖片參考：http://imgcld.yimg.com/8/n/HA00591740/o/701105220063413873442484.jpg

▲P.1892

2011-05-23 01:17:38 補充：
五張圖來自 OXFORD ADVANCED LEARNER'S E-C DICTIONARY (ISBN 0-19-590969-0)

I agree with ho-yin that the omission of "that" does not depend on whether it is followed by a noun. Radioman (aka fight gansters) is wrong again, but as usual, he will twist the facts and argue till hell freezes over. Fortunately his poor English, irrational logic, and foul language work against his credibility, so the more he argues or attacks, the less chance for his answer to be selected. I feel sorry for him, but he does have a choice to improve himself, respect others, and earn his acceptance in a positive manner, like everybody else.

我也是過路人, 無論是什麼人,在些不得無禮,辯論要保持風度,嚴禁"發老脾".
但求智識真相, 好勝誤己誤人.

2011-05-23 07:59:41 補充：
" You guys are trying to misleading the others."

You=你, / 你們.

to be .....misleading( ifinitive with continuous tense).... the others.

Radioman/Fight Gangster

我永遠也不會是你的partner(有人連partner都串錯)

無恥之徒，羞與為伍

Fight Gangster/Radioman/Iero/Funker:
... you guys are trying to MISLEADING the others. This is not a grammatical sentence. You who know the grammar rules should not have made such a mistake!

2011-05-22 20:28:12 補充：
It's no good trying your tricks on with us. You just keep dumping your crappy sentences with Tons of mistakes!

Direct speech:
Tom says " He will go to picinic on Sunday."

Indirect speech
Tom said that he would go to picnic on Sunday.

That should be kept in this sentence and when we rewrite a sentence from direct speech into indirect speech.