嘌呤核苷酸代谢的终产物为（），该产物增多导致的疾病称（）。
参考答案：尿酸；痛风症
外科感染按病变进展过程分为哪几类？
Whenever we met, Lily ________ greet me first though I was younger than her.[ ]
A. must
B. would
C. should
D. could
