重度二尖瓣狭窄的严重并发症是（）
A.心室颤动
B.甲亢
C.心房颤动
D.急性肺水肿
E.感染
参考答案：D
选矿过程分为哪几个阶段？
—Can I get you a cup of tea?
—______ [ ]
A. Thank you for the tea
B. With pleasure
C. You can, please
D. That’s very nice of you
