—__      does Mary usually go to the bubby club?

—Once a week.[ ]

A. How much    

B. How long        

C. How far          

D. How often  

干槽症通常发生在拔牙（）

A.1-2天后

B.2-3天后

C.3-5天后

D.5-7天后

E.7天后