实时荧光PCR检测粘附因子基因的多态性的最大优点是()
A.实时检测,不易出现扩增产物污染
B.可同时检测大量样本
C.准确性高
D.特异性好
E.简便快速
参考答案:A
---- Are you still a teacher?
---- No, I____ in Harbin No. 3 High School for five years.
A.worked
B.have worked
C.have been working
D.had worked
在标准状况下,560ml某气体的质量为1.1g,这种气体可能是( )
A CO B N2 C CO2 D N2O