☉ 理所当然 【lǐsuǒdānɡrán】
　　[ 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。
　　例： 就把来结识了这位大哥，也是理所当然。——明·冯梦龙《醒世恒言》