“Do you think he is lazy?” “I so once, but I don’t now.”
A. may have thought
B. can have thought
C. may think
D. might think
网友回答
(答案→)A. may have thought
B. can have thought
C. may think
D. might think
解析： 从答话人的语境可知，空格处的意思“曾经这样想过”，即对过去情况作推测，故应用“情态动词+动词完成式”；又因为 can 表推测不用于肯定句，故选A。