Students remain in their seats until all the papers have been collected.A. wouldB. shall

问题补充：

Students remain in their seats until all the papers have been collected.

A. would

B. shall

C. will

D. could

答案：

A. would

(答案→)B. shall

C. will

D. could

解析：答案：B考查情态动词。该空 shall表示规定、命令，故选B。