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

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：考查连词辨析。A以至于；B以防；C为了；D既然；结合句意可知B正确。句意：以防他们会干扰别人，老师让那两个学生小声讨论问题。