为了增加鲜牛乳的表面张力，一般情况下添加（）
A.加甲醛或抗生素
B.碳酸氢钠
C.明胶
D.尿素
E.水
参考答案：C
—Excuse me, would you mind answering a few questions?
—Well, I don't know. I'm in rather a hurry__________. [ ]
A. seriously
B. actually
C. immediately
D. anxiously
设u（x）与v（x）均为可导函数且v（x）≠0，则().
().