主动脉瓣关闭不全时的舒张期叹气样杂音是（）。
A.递增型杂音
B.递减型杂音
C.递增递减型杂音
D.连续型杂音
E.-贯型杂音
参考答案：B
The little boy is dirty from head to foot because he______in the mud all morning.
A．has played
B．is playing
C．has been playing
D．was playing
国家行政机关可否开展专业技术资格评审工作？
