单纯S1增强可见于（）
A.二尖瓣狭窄
B.二尖瓣关闭不全
C.甲状腺功能减退
D.心肌梗死
E.心房颤动
参考答案：A
_______ her parents were strongly against it, she married the young man.
A．For
B．If
C．Since
D．While
酶促反应中决定酶专一性的是
A．酶蛋白
B．辅基或辅酶
C．金属离子
D．底物
E．催化基团
