二次函数y=（x-1）2+2的最小值是 [ ]
A．2
B．1
C．-1
D．-2
答案：A
-- Why didn’t you come to attend our party last night ?
--- Sorry, Ｉ__________ an interesting programme on TV with my sister.
A．was watching
B．watched
C．have been watching
D．had watched
时间风险的含义不仅表现为选择合适的时机进入市场，还表现为物业持有时间的长短。（）
