“海峡浅浅,明月弯弯。一封家书,一张船票,一生的想念。相隔倍觉离乱苦,近乡更知故土甜。少小离家,如今你回来了,双手颤抖,你捧着的不是老兵的遗骨,一坛又一坛,都是满满的乡愁。”高秉涵帮助台湾老兵完成遗愿,回归故乡的事迹告诉我们( )
①两岸同胞手足情深 ②应该以实际行动为完成祖国统一大业多做贡献
③扶危济困是中华民族的传统美德 ④“一国两制”是实现两岸和平发展的政治基础
A:①②
B:②④
C:①②③
D:①②④
As we know,there 1 four seasons in China . It's 2 in spring(春), hot in 3 , cool in autumn(秋) and cold in 4 . My 5 season is winter. Sometimes it snows(下雪). Everything is all white. The world 6 clean and fresh(新鲜). I can go skating then. But Kitty likes summer 7 than winter. She says summer is 8 for sports. She can go 9 , sometimes in a lake and sometimes in a river. She 10 it very much .
75×4=____
(75×2)×(4×5)=____
(75×10)×(4×100)=____
(75×100)×(4×100)=____
如图所示,轻绳一端系一小球,另一端固定于O点,在O点正下方的P点钉一颗钉子,使悬线拉紧与竖直方向成一角度θ,然后由静止释放小球,当悬线碰到钉子时( )
①小球的瞬时速度突然变大
②小球的加速度突然变大
③小球做圆周运动所需的向心力突然变大
④悬线所受的拉力突然变大.