在时刻8:30时,时钟上的时针与分针之间的所成的夹角是( )
①M={ (x,y)|y=1x };
②M={(x,y)|y=sinx+1};
③M={(x,y)|y=log2x};
④M={(x,y)|y=ex﹣2}.
其中是“垂直对点集”的序号是( )
There is a common belief among the students in our school ______ they should try their best to learn and reach the peak of their academic performances.