______ the students found the soldier's idea interesting, the system was too difficult to be

of practical use.   [ ]

A. While      

B. Unless       

C. As soon as      

D. Even if

ADC288转印带加压机构由什么驱动的（）

A.主马达驱动

B.定影马达驱动

C.转印马达驱动

D.补粉马达驱动