fastness

"The student's ability to concentrate in noisy environments was crucial for success in the class. "

"The castle served as the king's stronghold, protecting him from invaders. "

"Our company uses a private internet to share documents securely among employees. "

"The connection between the two classrooms was established by installing a new phone line. "

"My sister is learning to play the guitar. "

"During the war, the city became a fortress against enemy attacks. "

"The strong bridge cables were designed to withstand the force of a major earthquake. "

"The teacher ensured her students that the test would cover only the topics they studied in class. "

"The parrot's feathers were colorful, with shades of green, blue, and yellow. "

"A secure supply of crude oil is crucial for any modern nation, let alone a superpower."

"We enjoyed a glass of fortified after dinner. "

"During the parade, soldiers marched proudly behind their national banners. "