问题补充：
—Why didn’t you attend the lecture yesterday?
—I didn’t think that we on Sundays.
A. should
B. ought to have
C. shouldn’t have
D. will have to
答案：
A. should
B. ought to have
(答案→)C. shouldn’t have
D. will have to
解析：首先排除B、D，B表示一种委婉，此时没必要，D项must语气不对。shall表单纯的将来，而will更好，表示我们将来愿意去。
