— You must get excited about going to France to study oil painting.

— ________, but I'm afraid I can't do well because my French is too poor.[      ]

A. I don't know yet  

B. Certainly not

C. Well, I ought to have  

D. All right

在配对比较的差值符号秩和检验中，如果有两个差值为0，则（）。

A.对正秩和有0.5和1，对负秩和有-0.5和-1

B.对正秩和有2，对负秩和有-2

C.对正秩和有3，对负秩和有-3

D.对正秩和有1.5，对负秩和有-1.5

E.0舍弃不计