---Have you seen _____ Audi car? I parked it here two hours ago, but now it’s gone!

---Is it _____ black one? A young man has just driven a black car away.

A．an…a

B．the…the

C．the… a

D．an…the

湿作业法石材墙面饰面板灌浆施工的技术要求是（）。

A.宜采用1:4水泥砂浆灌浆 

B.每层灌浆高度宜为150～200mm，且不超过板高的1/3 

C.下层砂浆终凝前不得灌注上层砂浆 

D.每块饰面板应一次灌浆到顶