

あんな人を信じたなんて、本当に愚かだった。
同じ失敗を何度も繰り返すのは愚かなことです。
失敗した人を愚かだと笑うべきではありません。
"おろかな(愚かな)" is in the lesson "Types of people" (Level 34), along with 10 other useful words. LinDuo has 180 topic lessons like this one, 2,379 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.