英语语法
过去情态动词（Past Modals）
“I must have lost it”（对过去的推测）、“she could have called”（没实现的可能）、“they might have already left”（对过去的猜测）、“it shouldn't have been done”（批评）。自然口语里“have”几乎都缩成 've，“should've”“could've”“must've”听起来跟“of”太像，连母语者写的时候都会误拼成“should of”。过去情态动词是学习者最头疼的地方之一，偏偏日常对话里出现得最多。
should / could / might / may / must + have + past participle
母语者的真实例句
"I should've marked it on the top because, the sticker clearly isn't enough, and the huge words decaf going on the side of your cup obviously wasn't enough either."
Confusing Coffee Order With A Decaf Latte
怎么用
公式
should / could / might / may / must + have + past participle
这一页把课本规则和真实英语放在一起：每个例子都是真人母语者的无脚本片段。你听到的是这个语法点在真实生活里怎么说，不是在课堂上怎么说。