理所当然（理所當然）　

◎ 理所当然 lǐsuǒdāngrán

[justifiably; a matter of course; as it ought to be; be both natural and right; it goes without saying; it is what propriety requires] 按道理应该如此

就把来结识了这位大哥,也是理所当然。——明· 冯梦龙《醒世恒言》