问题补充：
My attention was beginning to wander and therefore I am afraid that I the main point of the lecture.
A. had missed
B. missed
C. was missing
D. have missed
答案：
A. had missed
(答案→)B. missed
C. was missing
D. have missed
解析：根据句子意思,我的注意力开始不集中,因此我害怕我错过了这次讲座的主要观点.可知下文叙述的是过去发生的事情,也就是我注意力涣散时的事情,所以应该用过去时态,选B.
