— Hi, Lydia. Are you going to the concert on Friday?  

— I'd like to . But there are so many problems_____.[ ]

A. remained to be settled

B. remaining to be settled

C. remained settled

D. remaining settled

空段清扫器装在尾部（）的前面，清扫装载时偶尔落在空载段带条非工作面上的物料。

A．驱动滚筒

B．改向滚筒

C．托辊

D．都对