企业为维持一定经营能力所必须负担的最低成本是( )。A．固定成本 B．酌量性固定成

一个杯子的杯口朝下放在桌上，翻动3次杯口朝______，翻动4次杯口朝______，翻动奇数次杯口朝______，翻动偶数次杯口朝______．

You_______ a teacher. I_____ a student, my sister______ is a student, too.[ ]

A. am, is, are    

B. is, are, am  

C. are, am, is  

If you are not familiar ____ the topic, you may write something that is familiar ____ you. [      ]

A. with; with  

B. to; to  

C. to; with  

D. with; to

围绕能源开采，山西省构造的产业链是(    )

①煤-电-铝     ②煤-焦-化   ③煤-气-液    ④煤-铁-钢   ⑤煤-电-钢

A．①②③

B．②③④

C．①②④

D．③④⑤

乳癖调护