If John had worked hard, he would not be a beggar now.

應該是...
If John had worked hard, he would not have been a beggar now.

意思是：
如果Ｊｏｈｎ從前有努力過的話，他現在就不會成為乞丐了。　

關於type 0, type 1, type 2, and type 3的問題，以上這一句是屬於ｔｙｐｅ ３的。

這一句是conditional-clause 的一種, 我們通常把它分為四個類別, 就是你課本中的type 0, 1, 2 & 3


Type 0: 一定會發生的事/ 很大可能發生的
if Clause: Present Tense
Main Clause: Simple Present Tense
e.g.
If we heat the ice, it melts.



Type 1: if clause 可能發生
if Clause: Present Tense
Main Clause: Future Tense / will + infinitive
.e.g.
If you do not live so far away, I will go and visit you.


Type 2: if clause 一定不會發生或假設的事
if Clause: Past Tense
Main Clause: Future Past Tense / would + infinitive
e.g.
If I were a millionaire, I would donate half of my money to the charity


Type 3: 在過去沒有發生的事/ 已成事實不能改變的(有點馬後炮...)
if Clause: Past Perfect Tense
Main Clause: Future Past Perfect Tense/ would + have + Past Participle
e.g.
(用以上句子為例, if-clause 是If John had worked hard,而mainclause 是he would not have been a beggar now)
因為時光不能倒流, 所以John 成為乞丐已經是不可能改變的事實.

2007-11-19 18:50:43 補充：
剛剛在找到的資料, 希望幫到你...If John had worked hard, he would not be a beggar now.這一句是真的有可能的, 除了以上提及的那幾種type之外, 還有一種叫mixed conditionalsmixed conditionals用於形容一件帶假設性(現在或過去)的事件以一個verb form 包含兩種不同的conditional pattern

2007-11-19 18:51:31 補充：
e.g. mixed type 1& 2-If he died(type 2), he will (type 1)not see his son.

2007-11-19 18:52:29 補充：
mixed type 2 & 3-If the island were(type 2) still a tourist attraction, last week's earthquake would have caused(type 3) for more deaths.mixed type 3 & 2-If she had caught(type 3) the train, she would (type 2)arrive now.

should be:

If John had worked hard, he wouldn't have been a beggar.

Corret. That means John did not work hard therefore he is a beggar.