This is _____ useful book that we all need to read it. [ ]

A. such an

B. such a

C. so

D. so a

冰雪天，为了防止汽车打滑，下列措施哪种是不妥当的[ ]

A．在汽车轮上装链条  

B．在汽车行走的路面上撒砂子 

C．对汽车行走的路浇水  

D．在汽车行走的路面上铺煤灰渣