The teacher explained a second time, the students should have difficulty in doing the experiment.
A. although
B. in case
C. so that
D. but
网友回答
A. although
(答案→)B. in case
C. so that
D. but
解析：句意:老师又解释了一次，以防学生们在做实验时有困难。Although尽管；in case万一；so that以便；but但是。根据句意故选B。