In April, the weather in some places in Shanxi was really changeable. People still remember they have _______ four seasons in a week.
A:organized
B:experienced
C:described
D:travelled
依据《中国居民膳食指南》,大多数人每天摄入的食物中含量最多的应该是( )
1760丘
1800互
1830丘
1870正
蒸汽机
5
35
160
2060
水车
70
120
230
如图所示,两根互相绝缘、垂直放置的直导线ab和cd,分别通有方向如图的电流,若通电导线ab固定不动,导线cd能自由运动,则它的运动情况是( )