目前热泵热水器有哪几类？
参考答案：
按照主机循环方式主要有：氟循环和水循环两种；按照热源不同，热泵可分为空气源热泵、水源热泵和地源热泵。
The old man was the only person on the spot____ helped him ____ a series of facts as told
A．who, set up
B．who ,set down
C．which ,set out
D．that, set off
1.25 ×88 =1.25 ×8 ×11应用了哪个运算定律？若1.25×88 =1.25×80 +1.25×8，这是应用了哪个运算定律进行简算的？[ ]
A．乘法分配律
B．乘法结合律
C．乘法交换律
