阅读下面这首诗歌,然后回答问题。
苏堤清明即事
(南宋)吴惟信
梨花风起正清明,游子寻春半出城。
日暮笙歌收拾去,万株杨柳属流莺。
【注释】即事:歌咏眼前景物。
To his ____(快乐,喜悦), his son was admitted to a famous university.
近年来北方春季频繁发生沙尘暴,这是( )发展的表现。