Be careful when you come _______ the street, because the traffic is very busy at the moment.
A:across
B:behind
C:between
D:over
平行四边形有____个锐角.
函数fx=Asinωx+φA>0,ω>0,φ<π2的部分图象如图所示,则函数y=fx对应的解析式为( )