A．水能和风能
B．核能
C．太阳能
D．燃料燃烧得到的内能
答案：D
什么是过热器或再热器的顺流、逆流、混合流布置方式？这些布置方式有何特点？
What does the man mean [A] Wang Wei is always late. [B] Wang Wei was late yesterday. [C] Wang Wei was on time yesterday.
