某地民歌歌词:“羊肚子手巾三道道蓝,咱们见个面面容易拉话话儿难.一个在山上一个在那沟,拉不上话话儿招一招手.了的见那村村了不见人,泪蛋蛋抛在沙蒿蒿林.”这是因为( )
A:横断山区山高路远
B:青藏高原雪峰连绵
C:塔里木盆地黄沙连天
D:黄土高原沟壑纵横
⑴My father is practising English.____ A.
⑵I'm going to study Geography in middle school.____ B.
⑶He is going to ride his bike to school.____ C.
⑷My friend Sam is going back to the UK.____ D.
⑸It's time to have lunch.____ E.
如图所示.连着弹簧的小球套在水平杆上,弹簧自由伸长时,小球位于O点.小幅度向左或向右改变小球位置,小球仍能静止,现较大幅度改变小球位置,把小球移至A点后使其静止,然后释放.
如图,点O是正六边形的对称中心,如果用一副三角板的角,借助点O(使该角的顶点落在点O处),把这个正六边形的面积n等分,那么n的所有可能取值的个数是( )