唔明白呢句點解要加THAT

你發唔發現 He will be there on time 呢句野係可以獨立成為一句意思完整既句子?

其實好多時that 後面就係要用呢d句子,
例如:
--> You are sad.
--> I understand that you are sad.
雖然話唔用個that 後面都可以用呢d完整句, 但係用左that就一定要用
--> I understand your sadness.
X I understand that your sadness ( THIS IS WRONG)

2011-04-23 02:30:03 補充：
verb + ing 可以變做Gerund, 即係由動詞變身成既名詞
正如i understand your sadness中, sadness 都係一個名詞

ensure 後邊可以用to 既! 你自己上google打ensure to, 就搵到好多例子啦~

Q1. I(S) can't ensure( Vt) his being(O) on time. 是一般的[ 陳述句] = SVO.


Q2. I(S) can't ensure(Vt) that he will be there on time.(O) 是clause中的 noun clause,
(that)是從屬連詞subordinate conjunction,引領整句作object. "that"=他將準時在該處.

noun clause 作object時是可將that隱藏.
=I can't ensure XXXX he will be there on time.

如從句作subject時,一定要that.
= That he will be there on time is not ensured to me.