装置停蒸汽,芳烃抽提要改循环操作。
参考答案:错
Her mother is a (n) ______. I often read her articles in the magazines. [ ]
A.actress
B.musician
C.teacher
D.author
处理不当可引起上总义齿左右翘动的是
A.主承托区 B.副承托区 C.缓冲区 D.边缘封闭区 E.后堤区