-----Mr. Smith, can I come to ask for some advice on my paper at any time?

-----Yes, of course.             .

A．If you’re convenient

B．At your convenience

C．That’s right

D．Don’t mention it

代谢性酸中毒可发生于

A．急性肠梗阻
B．感染性休克
C．肺炎高热
D．慢性十二指肠瘘
E．急性肾功能衰竭