读一读,写一写
①— Are there any ____ ?
— Yes, there are.
②There are many tall ____ in my city.
③There is a ____ above the river.
④- Are there any houses in the ____?
-Yes, there are.
在Rt△ABC中,∠C=90°,cosA=13,AC=2,那么BC=____.
从距离地面5m的高处将质量为0.5kg的物块以5m/s的速度水平抛出,不计空气阻力,g取10m/s2.求:
下列关于第一次世界大战爆发前的各大国关系的表述,不正确的是( )