对于约束性固定成本,下列描述正确的是()
A.是企业必须开支的成本
B.预算期较短
C.管理当局可以视情而定
D.成本的数额不具有约束性
参考答案:A
已知A=x3﹣10x﹣6,B=﹣2x3+2x2﹣1;C=﹣(3x2﹣4x2);
计算:A﹣(B+C);并求当x=﹣2时,A﹣(B+C)的值.
_______ you have been to America for many times, you must know something about this country. [ ]
A. Since
B. Although
C. Unless
D. When