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

问题补充：

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

A. shall

B. might

C. could

D. will

答案：

(答案→)A. shall

B. might

C. could

D. will

解析：句意：试卷全部收回后学生才可离开座位。shall用于第二、三人称，表示命令、警告或允诺，符合句意。