差量损益既是差量收入与差量成本之间的数量差异，又是两个备选方案的预期收益之间的数量差异。
参考答案：错
多项式x2﹣ax﹣35因式分解为（x﹣5）（x+7），则a=（ ）。
----Is this the first time you _____Chengdu ?
----No. But the first time I _____here, the city wasn't so beautiful.
A．visited, came
B．visited, have come
C．have visited, have come
D．have visited, came
