原核生物DNA指导的RNA聚合酶由数个亚单位组成，其核心酶的组成是
A．α2ββ'B．α2ββ'σC．ααβD．αββ
参考答案：A
改错，将句中错误部分的序号填入题前的括号，并将正确答案填在横线上。
( ) 1. How old is it from here to there? ________________
A B C
( ) 2. About two thousands kilometres. ________________
( ) 3. That's about three hundred kilometre. ________________
( ) 4. Can you say this numbers? ________________
( ) 5. It's only sixty eight kilometres. ________________
6kV快切装置“开位异常”是怎么回事？
