本條件句的第一部份描述一個不實際或虛假的狀況，第二部份則陳述如果該狀況為真時，會發生的後果。
不實條件句（反白標明者）的 "if" 子句描述了一個不實際或虛假的狀況。在這個情況下，說話者不知道電話號碼為何。這可由句中的 "if" 和動詞的過去式得知。
結果子句（反白標明者）陳述一旦 "if" 子句的情況為真時，將會發生的事情。不過，因為 "if" 子句是描述不實際的情形，所以不會發生。
整個句子的意思是說話者想要打電話確認訂單，但是因為不知道電話號碼，所以無法這樣做。請注意，當 "if" 子句置於句首時，後面要加上逗號。
請留意這些有關現在及未來不實情況的條件句之句型。在 "if" 子句中，會使用過去式的動詞。在結果子句中，動詞之前通常會加上 "would"。
若使用 "be" 動詞，請用 "were" 的形態，即使主詞為 "I"、"he"、"she" 或 "it" 時亦然。不過，在比較不正式的情況下，也可以使用 "was" 。
否定句的句型為將 "didn't" 置於 "if" 子句內的動詞前面，或將 "not" 置於結果子句內的 "would" 後面。
If I knew the phone number, I would call to check on the order.
結果子句（反白標明者）陳述一旦 "if" 子句的情況為真時，將會發生的事情。不過，因為 "if" 子句是描述不實際的情形，所以不會發生。
整個句子的意思是說話者想要打電話確認訂單，但是因為不知道電話號碼，所以無法這樣做。請注意，當 "if" 子句置於句首時，後面要加上逗號。
If clause result
-------------- --------------
past form would+base
If I knew......., I would call..........
請留意這些有關現在及未來不實情況的條件句之句型。在 "if" 子句中，會使用過去式的動詞。在結果子句中，動詞之前通常會加上 "would"。
If he left this company, he wouldn't have any difficulty finding a new job. ->
He wouldn't have any difficulty finding a new job if he left this company.
UNREAL CONDITIONAL SENTENCES IN THE PRESENT AND FUTURE
Example:
| If I knew the phone number, --I would call to check on the order. | (I don't know the number, --so I can't call to check on the order.) |
Postive Sentences | "If" Clause If S V (past tense) If I knew the phone number, | Result Clause S would V (base form) I would call to check on the order. |
| With "be" | If S were | S would V (base form) |
| If I were you, I would stay home today. | ||
| With "be" (less formal) | If S was | S would V (base form) |
| If she was having personal problems, she would tell me. | ||
| Negative Sentences | If S didn't V (past tense) | S would V (base form) |
| If she didn't have so much to do, she would feel less stress. | ||
| OR | If S V (past tense) | S wouldn't V (base form) |
| If he left the company, he wouldn't have any difficulty finding a new job. | ||
The order of the clauses doesn't matter.
If he left the company, he wouldn't have any difficulty finding a new job.
He wouldn't have any difficulty finding a new job if he left the company.
He wouldn't have any difficulty finding a new job if he left the company.
