食品加工过程可以分解为一系列单元操作的组合，这些单元操作的机理是（）。

A.动量传递

B.数量传递

C.热量传递

D.力量传递

E.质量传递

Even though we had lost the（）of our family, everyone came on Christmas Day—making an effort to be cheerful.

A.bachelor

B.master

C.doctor

D.postdoctor