A:热机做的有用功越多,效率就一定高
B:热机的功率大,效率就一定高
C:热机消耗的燃料越多,效率就越低
D:热机内能转化成机械能的百分比越大,效率越高
A. Buckingham Palace B. Hyde Park
C. Tower Bridge D. Big Ben
E. a book about London