◇ Modal Verbs - Must have
助動詞 Must have 用法
情態動詞過去式是種對過去的猜測，根據現在已知的資訊去推測過去的狀況。情態動詞過去式的形式為情態動詞 ＋ have ＋ 過去分詞，例如例句 He must've felt like he never had enough soldiers to go around. 其中的 must've felt 是 must have felt 的縮寫，使用情態動詞 must 加上 have 推測過去某件事「一定」有發生。其他用法還有 could have「本來可以」和 should have「應該要」等等，以下舉例做說明。
Example：
1. The light was out, so they must have gone to bed.
熄燈了，所以他們一定睡了。
2. The governor could have been a candidate for the presidential election, but rumors of him having an affair killed his chance.
這位州長本來能成為總統大選的候選人，但是出軌的傳聞扼殺了他的機會。
3. I should have taken his advice to invest in that startup company.
我應該聽取她的建議去投資那間新創公司。