folly

"His foolishness in arguing with the teacher led to a detention. "

"She is investing time in studying for her exams to get a good grade. "

"The school was able to build a new library thanks to a generous benefactor who donated a large sum of money. "

"Her thoughtless remark about his weight really hurt his feelings. "

"The lack of sleep resulted in a poor performance on the math test. "

"The author's extravagant claims about the alien encounter stretched far beyond any credible evidence. "

"My grandmother's garden has many beautiful ornamental plants. "

"The practical for the carpentry course was building a small table. "

"My old car is unreliable; it often breaks down on the way to work. "

"A problem ignored is a problem doubled."

"Hey, beautiful!"

"If you miss your curfew, a consequence is having to stay inside and do chores. "