二尖瓣开瓣音可出现于()
A.二尖瓣关闭不全
B.左心房黏液瘤
C.二尖瓣狭窄
D.缩窄性心包炎
E.二尖瓣脱垂
参考答案:C
Under the Companies Ordinance, 1984;
(b) explain the requirements for the appointment and removal of a ‘chief executive’. (7 marks)
钻进过程中,一旦发现“见软”、“见空”、“见水”和变层,要立即停钻,丈量()并记录其深度。