"The problem would be solved if you could tell me that earlier."
「要是你現在早一點告訴我，問題可能解決了。」
這句話表達與現在事實相反的假設語氣，同樣的事件也可以這樣表達：
"The problem would be solved if you told me that earlier."
這兩個句子主要的差異在於，情態助動詞 could 可以讓語氣更加委婉，降低指責的
尖銳程度。
同理，在表達與過去相反的假設語氣時，情態助動詞也扮演相同的功能：
"The problem would have been solved if you could have told me earlier." → 語氣較委婉
"The problem would have been solved if you had told me earlier." → 語氣較尖銳 |
