Chinese people usually enjoy the moon______ the evening____ the Mid-Autumn Festival.
A:in; for
B:on; at
C:in; on
D:on; of
—Sure, I'd like to. What kind of exhibition is it?
“25寸”彩电的大小是指( )
已知向量 a→ =(2,6), b→ =(﹣1,λ),若 a→∥b→ ,则λ=____.