.No matter how fast we worked,____.

A．we couldn’t catch up with them

B．and we couldn’t catch up with them

C．so we couldn’t catch up with them

D．but we couldn’t catch up with them

《汉书》中“八表”和《天文志》的补作者之一是（）

A.班超

B.班昭

C.尹敏

D.孟异