丹凤千字科普：if引导的从句位置（详细资料介绍）

1. "as if/as though+主语＋could/might/would+动词原形"（与将来的实际情况相反）。如：“那位老太太看上去好像还能再活一百年。”原本的表达是"It looks as if the old woman could live other hundred years."

2. "as if/as though+主语＋动词过去式"（与现在或当时的实际情况相反）。例如：“他们刚刚见面，但交谈起来就像老朋友一样。”原本的表达是"They have just met but they are talking as if they were old friends."

3. "as if/as though+主语＋were doing"（与正在发生的实际情况相反）。例如：“他们跑得飞快，就像有鬼在追他们。”原本的表达是"They ran as fast as they could as if a ghost were chasing them."

4. "as if/as though +主语＋had+过去分词"（与过去的实际情况相反）。例如：“他的吃相就好像他很多年没吃过饭似的。”原本的表达是"He ate as if he hadn't had a meal for years."