朗肯循环是对卡诺循环在某些热力过程的改进，因而在实际中易于实现，但其效率在理论上比卡诺循环要低。
参考答案：错
Chinese and Maths ______ my favourite lessons. [ ]
A. all are
B. both are
C. are all
D. are both
怎样制备“无钠水”？
