大气中的降水量,有________渗入土壤,有________被树冠截留及蒸发。
50%~80% 15%~40%
_____ mothers work in the same hospital.[ ]
A. Tim and Peter's
B. Tim's and Peter
C. Tim's and Peter's
D. Tim and Peter
化学补充水补入热力系统时应考虑哪些问题,应如何选择补入点?