— Would you like to go out for a walk with us? 

— _______, but I must finish my homework first. [ ]

A. That's all right

B. Yes, I do

C. I'd love to

D. Of course not

若正常人体内血糖浓度达到或超过0.16%时，会暂时出现尿糖现象．只是因为（　　）

A．胰岛素分泌过少

B．肾小球发生病变，过滤作用过强

C．肾小管的重吸收能力有限

D．肾小管发生病变并失去重吸收能力