"As if" 和 "as though" 都表示假设、比喻或类似的意思，通常用于描述一种情况或行为，暗示这个情况或行为并不是真实的。虽然它们可以互换使用，但根据句子的结构和语境，可能更倾向于使用其中之一。
大家可以先看下面的表格了解一下 dream of 和 dream about 吧：
"as if" 和 "as though" 的区别：
区别1：虚拟情况的强度
"as if": 强调更不真实或与事实更不符的情况。
例子1: He acted as if he were the king. (他的举止就像他是国王。)
例子2: She talked about it as if she knew everything. (她谈论起来像是对一切都了如指掌。)
"as though": 强调看起来是真实的或可能更接近实际情况的虚拟情况。
例子1: He looked at her as though he loved her deeply. (他看着她，仿佛深深地爱着她。)
例子2: The child acted as though he understood the complex problem. (那个孩子的举止让人觉得他好像理解了这个复杂的问题。)
区别2：描述外貌或行为
"as if": 主要用于描述外貌、行为或态度，以暗示它们的真实性或可信度。
例子1: She smiled as if she had just won a lottery. (她微笑着，好像刚刚中了彩票。)
例子2: He walked as if he was carrying a heavy burden. (他走路的样子像是背负着沉重的负担。)
"as though": 同样可以用于描述外貌、行为或态度，但更强调它们看起来是真实的或可能接近实际情况。
例子1: The girl spoke as though she knew the answer to the question. (那个女孩说话的样子好像知道那个问题的答案。)
例子2: He laughed as though he found the joke extremely funny. (他笑得好像觉得这个笑话非常有趣。)
区别3：交换使用
"as if": 更常用于英式英语和美式英语。
例子1: It looks as if it's going to rain. (看起来要下雨了。)
例子2: He acts as if he knows everything. (他的举止好像他什么都知道。)
"as though": 更常用于英式英语，但在美式英语中也可见。
例子1: It seems as though she is upset. (她看起来有些心烦意乱。)
例子2: She talks as though she has experienced it firsthand. (她说话的样子像是亲身经历过一样。)
区别4：口语和正式语境
"as if": 在日常口语和书面语中都可以使用。
例子1: It's as if he doesn't care about anyone else. (好像他不在乎别人一样。)
例子2: She speaks as if she owns the place. (她说话的样子就像她是这个地方的主人一样。)
"as though": 通常在正式语境或较为文学化的表达中使用。
例子1: The old man looked as though he had seen a ghost. (老人的神情好像看到了鬼一样。)
例子2: The building stands as though it has been there for centuries. (这座建筑物似乎已经立在那儿有好几个世纪了。)