A:what the matter i
B:what is the wrong
C:what is the matter
D:how matter stood
天空中有那么多风筝。
There are____ ____kites in the sky.
质点做直线运动,其位移随时间变化的函数关系是s=4t+2t2(s的单位为m,t的单位为s),则它运动的初速度v0和加速度a分别是( )