_________ he was exercising in the park yesterday morning, he found a purse under the tree.
A:While
B:Before
C:After
某市政府根据中央精神,将本级政府的权力清单在官方网站向社会公开。此举影响的正确路径是( )。
2角=____元
下列关于空气成分的说法错误的是