lubricating

"The oil lubricates the bicycle chain, making it easier to pedal. "

"To minimize noise from the street, we closed all the windows. "

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

"The bike chain was squeaking loudly, so I applied lubricant to it to make it run smoothly. "

"My brother is an engineer; he designs and builds bridges. "

"The mechanic fixed the broken bicycle chain. "

"The ancient Romans used a powerful siege engine to break down the city walls. "

"I brush my teeth regularly to prevent them from turning yellow."

"The smooth transition between classes made it easy to get to my next lesson. "

"to apply cream to a rash"

"My brother normally gets up early for school. "

"Oily substances render things slippery."