一、文法不同
as if 引导的方式状语从句或表语从句，用虚拟语气。
例句： He acts as if he knew me. 他显得认识我似的。
as though 表示与现在事实相反，谓语动词，用would (might, could)+动词原形。
例句：They treat me as though I were a stranger. 他们待我如陌生人。
二、时态不同
as if 表示与过去事实相反，用过去完成时。
例句：This meat tastes as if it has already gone bad. 这肉吃起来似乎已经坏了。
as though 表示将来的可能性不大，用一般过去时。
例句：I feel as though I’m floating on air. 他感到好像漂浮在空中。
三、语境不同
as if 用来描述比较悲惨的境遇或者状况。
例句：It is not as if he were poor. 他不像穷的样子(或他又不穷)。
as though 语境属于中性，可以用到很多情境中。
例句：It is not as though you were going away for good. 又不是你离开不回来了。
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第1个回答 2023-03-26
Holding his head high, he walked past the pole and the soldiers as
if they didn’t exist.
as if 与as though 是一组同义词，两者意思相同，用法也相同，只是在口语中人们多半会用as if, 取其简短。as if
和as though 用法较为复杂，本文拟对其各种用法做一概述。

1．在通常情况下， as if 和as though 所引导的从句的谓语动词多用虚拟语气，表示所叙述的情况与事实相反。具体用法如下：
1)谈论现在情形的，用过去时（动词be用were,也可用was）：
Why is she looking at me as though she knew me? 他为什么那样看我？像是认识我似的。
He behaves as if he owned the house. 他的样子好像他拥有这个房子。 He treats me as if /as though I were a stranger.
He speaks as if he were an Englishman.
It’s not as though he was /were poor.
2)谈论过去情形的动词形式有以下几种：
a)过去式，表示过去的状态，如：
He looked at me as if I were mad. 他那样看我，好像我是个疯子。
He stood there looking at the train and laughing, as if to miss a
train was the best joke in the world.
他站在那里，望着火车哈哈大笑，好像误了火车是天底下最开心的事儿似的。 Mr. Coleman always talked as if he knew everything.
但是，如果状态动词带有持续时间状语，则用过去完成时：
They talked as if they had been friends for years. (高二册，第95页) (试比较：They had been friends for years.)
Now it is as though she had known Millie for years. (《现代英语用法词典》) 情态动词亦用过去时：
She felt as though she could hardly endure such a life.
她觉得简直无法忍受这样的生活。
b)过去完成时，表示过去的动作先于主句动词而发生或完成，如： It was as if he had lost his last friend.
“I remember,” she tells her children now, “how wild his white hair
looked——as if it had been electrified.”（高二册，第91页）
必须注意的时，在指过去的动作时，即使主句是现在时，as if 从句中的动词也要用过去完成时：
You look as if you’d seen a ghost. 你好像是见了鬼似的。
He talks about Rome as though he had been there himself.
他讲起罗马的情况来就好像他亲自到过那里似的。
c)过去进行时，表示动作正在进行：
He heard a noise, as if someone was breathing.（高一册，第211页） He ran as if ghosts were chasing him.
I felt as if the ground were slipping beneath my feet. 我感到大地仿佛在脚下滑动。
d)过去将来时，表示将要发生的事态：
It looked as if it was going to snow. （高一册，第127页）本回答被网友采纳
if they didn’t exist.
as if 与as though 是一组同义词，两者意思相同，用法也相同，只是在口语中人们多半会用as if, 取其简短。as if
和as though 用法较为复杂，本文拟对其各种用法做一概述。

1．在通常情况下， as if 和as though 所引导的从句的谓语动词多用虚拟语气，表示所叙述的情况与事实相反。具体用法如下：
1)谈论现在情形的，用过去时（动词be用were,也可用was）：
Why is she looking at me as though she knew me? 他为什么那样看我？像是认识我似的。
He behaves as if he owned the house. 他的样子好像他拥有这个房子。 He treats me as if /as though I were a stranger.
He speaks as if he were an Englishman.
It’s not as though he was /were poor.
2)谈论过去情形的动词形式有以下几种：
a)过去式，表示过去的状态，如：
He looked at me as if I were mad. 他那样看我，好像我是个疯子。
He stood there looking at the train and laughing, as if to miss a
train was the best joke in the world.
他站在那里，望着火车哈哈大笑，好像误了火车是天底下最开心的事儿似的。 Mr. Coleman always talked as if he knew everything.
但是，如果状态动词带有持续时间状语，则用过去完成时：
They talked as if they had been friends for years. (高二册，第95页) (试比较：They had been friends for years.)
Now it is as though she had known Millie for years. (《现代英语用法词典》) 情态动词亦用过去时：
She felt as though she could hardly endure such a life.
她觉得简直无法忍受这样的生活。
b)过去完成时，表示过去的动作先于主句动词而发生或完成，如： It was as if he had lost his last friend.
“I remember,” she tells her children now, “how wild his white hair
looked——as if it had been electrified.”（高二册，第91页）
必须注意的时，在指过去的动作时，即使主句是现在时，as if 从句中的动词也要用过去完成时：
You look as if you’d seen a ghost. 你好像是见了鬼似的。
He talks about Rome as though he had been there himself.
他讲起罗马的情况来就好像他亲自到过那里似的。
c)过去进行时，表示动作正在进行：
He heard a noise, as if someone was breathing.（高一册，第211页） He ran as if ghosts were chasing him.
I felt as if the ground were slipping beneath my feet. 我感到大地仿佛在脚下滑动。
d)过去将来时，表示将要发生的事态：
It looked as if it was going to snow. （高一册，第127页）本回答被网友采纳
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