Conditional sentences 有 4 種，分別是 Type 0, Type 1, Type 2 and Type 3。
Type 2
Refers to an unreal/imagined situation or something that is unlikely to happen at the moment or in the future.
(表示現階段或將來不太可能發生的事，例如中六合彩頭獎; 表示一個想像的情境)
David would buy a big house if he had five million dollars.
If David had five million dollars, he would buy a big house.
這兩句是一樣的，但要留意 comma(逗號)的運用。
它的句子的結構(form)是這樣的：
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