The teacher asked the two students to discuss the question in a low voice they should bot

问题补充：

The teacher asked the two students to discuss the question in a low voice they should bother the others.

A. so that

B. in case

C. in order that

D. now that

答案：

A. so that

(答案→)B. in case

C. in order that

D. now that

解析：考查连词：A. so that为了，以至于，B. in case以防，C. in order that为了，D. now that既然，句意是：老师让两个学生低声讨论问题，以防打扰其他同学。选B。