理想制冷循环就是（）。
A.可逆循环
B.不可逆循环
C.卡诺循环
D.逆卡诺循环
参考答案：D
–Excuse me, I’d like a pair of shoes.
－What about this _______? You can try ______ on.
A．one, it
B．pair, it
C．one, them
D．pair, them
体育活动对心理健康的影响有哪些？
