— Do you mind if I open the window to let in some fresh air?

—  ______.

A. Never mind

B. No, go ahead

C. No, you'd better not

D. Of course, go ahead

常见以急性和亚急性起病的三类神经系统疾病是

A．肿瘤、感染、血管性病
B．外伤、感染、血管性病
C．退行性变性、感染、血管性病
D．遗传代谢病、感染、血管性病
E．肿瘤、遗传代谢病、退行性变