A:北温带、亚热带和热带
B:北寒带、北温带和亚热带
C:热带、亚热带和南温带
D:南寒带、南温带和亚热带
元代《琵琶记》中说:“十年寒窗无人问,一举成名天下知。”这句话反映的社会现象在中国最早出现的时间是( )
某索道全长2400m,上、下高度差约600m。如图所示的吊车重约1500N.求:(1)若吊车与钢索的接触面积为0.01m2,索道上挂吊车处的钢索承受的压强是多大?(2)若吊车从索道最高处运行到最低处,需时20分钟,吊车的速度是多少?吊车的重力总共做了多少功?
阅读理解,判断正(√)误(X)
I went to Chengdu three years ago. It is in Sichuan Province(省). It is the capital of Sichuan. It is in the west of China. The famous Chinese pandas live in Sichuan. I took some pictures for them. I climbed the mountains(山) with my parents.We had an interesting life.