______ it ______ for your help, I couldn’t have made any progress.

A．Had; not been

B．Should; not been

C．Did; not been

D．Not; been

关于糖尿病神经病变的叙述正确的是

A．部位以周围神经最常见

B．下肢较上肢严重

C．通常为不对称性

D．植物神经病变不常受累

E．临床病变表现为间歇性跛行