it用作形式主語或形式賓語的用法

1. it用作形式主語

當(dāng)不定式、動名詞、從句等用作主語時，為避免頭重腳輕，通常在句首使用形式主語it，而把真正的主語放在句子末尾。如：
It’s a pity to refuse. 拒絕是令人遺憾的。
It’s no use saying any more about it. 再談這事沒有用。
It’s not known where she went. 她到哪里去了沒人知道。
注：It is said / reported / believed / understood that… 這類結(jié)構(gòu)中的 it 也是形式主語。如：
It’s reported that two people were injured in the accident. 據(jù)報導(dǎo)這次事故中有兩人受傷。

2. it用作形式賓語

當(dāng)不定式、動名詞、從句等用作賓語且其后跟有賓語補(bǔ)足語時，就應(yīng)在賓語補(bǔ)足語前使用形式賓語，而將真正的賓語移至句末。如：
I find it easy to get on with her. 我發(fā)現(xiàn)她很容易相處。
I think it best that you should stay here. 我認(rèn)為你住這兒。
They haven’t made it known where they are to hold the conference. 他們還沒宣布會議在哪里開。

幾種特殊的形式賓語it

1. enjoy, like, dislike, love, hate, prefer, appreciate等動詞后接 if 從句或 when 從句，通常應(yīng)先在動詞后接 it 作形式賓語。如：
She won’t like it if you arrive late. 她不喜歡你遲到。
He hates it when people use his bike. 他討厭別人用他的自行車。
I hate it if you say such things in public. 我討厭你在大庭廣眾之下說那樣的事。
I’d prefer it if I didn’t have to do so much work. 要是我不必做那么多工作，那就太好了。
I would appreciate it very much if you would help me with it. 如果你能幫助我做這事，我會十分感激。