单项选择题
A.Any surge occurs B.Any surge occurred C.Should any surge occur D.Should any surge occurring
（）, the motion would continue indefinitely once it had ...
单项选择题（）, the motion would continue indefinitely once it had started.
A.Were there loss of energy by friction B.Since there be loss of energy by friction C.Were there no loss of energy by friction D.Should be no loss of energy by friction
（） the bodies are, （） the friction will be.A.The smooth...
单项选择题（） the bodies are, （） the friction will be.
A.The smoother；the greater B.Smoother；less C.The rougher；the greater D.rougher；greater
Convection is the principal means （） temperature is equ...
单项选择题Convection is the principal means （） temperature is equilibrated in liquids and gases.
A.in which B.on which C.by which D.from which
