—Do you think we can get there on time?

—Yes，_______ the truck doesn’t break down. 　

A．even if 　

B．unless

C．until 　

D．so long as

评价治疗前后红细胞沉降率是否有差别的检验假设（）

A．治疗前后总体均数μ₁＝μ₂

B．μ₁≠μ₂

C．治疗前后差值总体均数μ＝0

D．治疗前后样本均数x₁≠x₂

E．x₁≠x₂