题干
– The terrible accident is under investigation.
--Actually, quicker action _____ those workers trapped in the mine.
--Actually, quicker action _____ those workers trapped in the mine.
A：might have saved
B：must have saved
C：should have saved
D：could have saved
答案(点此获取答案解析）
D
），则f（ 
）的值为（ ）