锅炉加药采用（），可以很容易地控制加药量。
参考答案：柱塞泵
劳动合同履行和集体合同履行都应当遵循( )的原则。
A．亲自履行
B．全面履行
C．诚实信用
D．协作履行
Perhaps more than anything else, it was onerous taxes that led to the Peasants’ Revolt in England in 1381.()
A. multiple
B. unjust
C. burdensome
D. infamous
