题干
He wouldn’t give up smoking _______ his doctor told him it was a matter of life and death.
A：except
B：after
C：until
D：in case
答案(点此获取答案解析）
C
的
醇类有a种结构，而分子式为CnH2nO2 (n≥1) 的羧酸类有b种结构，则a和b的大小关系为
