We are planning to have a surprise party ________ her fifteenth birthday
A:at
B:in
C:for
D:with
下列有关“温鼎”的解说,不正确的一项是( )
一艘轮船以速度15m/s匀速运动,它所受到的阻力为1.2×107N,发动机的实际功率是( )