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：need have saved
D：could have saved
答案(点此获取答案解析）
D
等阴离子。某同学取5份此溶液样品，分别进
行了如下实验：
三种阴离子。
H＋＋OH－，下列叙述正确的是