诊断颅底骨折通常依据是（）。

A.头颅X线摄片

B.受伤机制

C.剧烈头痛伴呕吐

D.临床体征

E.意识障碍

—Excuse me, what's  this for?  

—It's a cleaner and it     ____ to pick up dirt.[ ]

A. uses                    

B. is used    

C. is using                

D. used