如图所示,小球沿足够长的斜面向上做匀变速运动,依次经a、b、c、d到达最高点e。已知ab=bd=6 m,bc=1 m,小球从a到c和从c到d所用的时间都是2 s,设小球经b、c时的速度分别为vb、vc,则( )
There are ________ months with _______ days in a year.
—Do you have ________ shells? —Yes, I have ________.
The Great Wall is about 2,000 years_______.
You’ll be late ________ you don’t hurry.
Listen to ________ music of the film.