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
读太阳光照局部图(如图),其中阴影部分表示黑夜,回答下题.
红领巾,按角分属于____三角形,按边分属于____三角形。