enforcing

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

"It is not necessarily true that children get their morals from their parents."

"The bus is approaching the stop, so get ready to board. "

"The children physically exhausted themselves playing tag in the park. "

"strengthen a muscle"

"The student used the new vocabulary list to learn the names of different flowers. "

"Attending all your classes is of great importance to your success in school. "

"The noisy environment of the school cafeteria made it difficult to concentrate on my homework. "

"Exercise is invigorating."

"The perpetrator of the vandalism in the school hallway was caught by security cameras. "

"Suzanne collected all the papers she had laid out."

"The medieval city's fortifications, including its high walls and deep moat, protected it from attack. "