在下列各种关税中，税率平均水平最高的是（）。
A.普惠税
B.普通税
C.最惠国税
D.特惠税
参考答案：C
---- Where is mother?
---- She is in the kitchen. She ______ the housework all morning.
A．was doing
B．has done
C．has been doing
D．is doing
气短声低，喉中时有轻度哮鸣，痰多质稀，色白，自汗，怕风，，常易感冒，倦怠无力，食少便溏，舌质淡，苔白，脉细软。证属( )
A．寒包热哮证B．风痰哮证C．肺脾气虚哮证D．肺肾两虚哮证
