undermining

"Her confidence in her ability to speak French helped her to participate more in class discussions. "

"My friend told me there was something in the box, but I didn't know what it was yet. "

"The underneath of the aircraft was painted blue."

"They bickered about dinner every evening."

"The student undermined the sandcastle by digging a tunnel beneath it. "

"Her resignation from the company was announced yesterday. "

"The politician received a lot of public criticism for his controversial stance on the issue."

"The storm was incredibly destructive, tearing down trees and damaging many homes. "

"My mother is always criticizing my messy room. "

"He spent six years in the military."

"After many frustrating attempts, he eventually finished his school project. "

"The foundation of his institute has been wrought with difficulty."