问题
选择题
“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
答案
答案：A
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。