机体嘌呤代谢障碍可引起（）
A.皮肤卟啉病
B.皮肤淀粉样变
C.鲍温病
D.毛周角化病
E.痛风
参考答案：E
--- Tom, why didn’t you come to the meeting yesterday?
--- I _____, but my car broke down.
A．would
B．had
C．was going to
D．did
共价键
