substratum

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

"Brush your teeth."

"Before the big exam, Maria felt a strong anxiety about failing. "

"The underneath of the aircraft was painted blue."

"Little grew on the farm, after the floods from the hurricane washed away the topsoil."

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

"The enzyme lactase helps digest lactose; lactose is the substrate in this reaction. "

"The ancient librarian was known for her vast knowledge of history. "

"Apply pressure to the wound to stop the bleeding."

"The archeologists carefully examined the ancient pottery shards. "

"The heavy box underlying the lighter one caused the whole stack to wobble. "

"There is one sterling and here is another"