She is a good student, ______ she?[ ]
A. is
B. isn't
C. does
D. doesn't
答案：B
影片拷贝的技术鉴定分为五个等级：甲、乙、丙、丁、戊，通常称为五级鉴定。
常压侧线产品为什么要精制？
