“I bought this shirt for 35 yuan yesterday.”“It’s on sale today for only 29.You should have waited.”“On really?But how _
问题描述：
“I bought this shirt for 35 yuan yesterday.”“It’s on sale today for only 29.You should have waited.”“On really?But how _____ I know?”
A:would
B:can
C:did
D:do
答
A
过去将来