sliding

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

"The cessation of the rain allowed the children to finally play outside. "

"a continuous current of electricity"

"The friction between the pencil and paper allows us to write. "

"He listened carefully to his mother's concerns, feeling sorrowful about her disappointment. "

"High-heeled shoes may be fashionable, but they can also be a hindrance to walking."

"The school's playground was a favorite spot for the children after their classes. "

"I think this piece connects to that piece over there."

"The small stain on his shirt went unnoticed during the important meeting. "

"The only perceptible was the faint sound of the clock ticking in the otherwise silent room. "

"No one noticed that he had moved imperceptibly backwards."

"My sister inadvertently left the oven on, causing the kitchen to overheat. "