进行厨房机构设置的前提是分清并把握（）、各工种职能。
参考答案：各部门
分解因式：x3y3-2x2y2+xy=______．
—What's your favorite subject?
—English. I like it very much ______ it's interesting and useful. [ ]
A. when
B. after
C. if
D. because
