就特征而言,日冕洞类似于( )
A:耀斑
B:太阳黑子
C:太阳风
D:日珥
图上距离一定比实际距离小.
Being happy is a skill that can be learned like a foreign language, and one way to ______ ourselves to be happy is to write down the little things that cheer us up each day.