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"The builder carefully placed the keystone at the very top of the arch, locking all the other stones in place. "

"Clouds were forming interesting shapes in the sky. "

"A series of seemingly inconsequential events led cumulatively to the fall of the company."

"My backpack was securely fastened to the chair, so I knew my books would stay put during the presentation. "

"Stick a wedge under the door, will you? It keeps blowing shut."

"This wall is made of bricks."

"The doorway to the classroom was crowded with students waiting for the bell. "

"He completed the assignment on time."

"The school's auditorium featured a beautiful stone vault, which created a high, impressive ceiling. "

"If you put the brakes on too hard, the wheels will lock."

"The potter shaped the clay into a beautiful vase. "

"Children collected colorful stones from the beach to decorate their sandcastle. "