goldmine

"My knowledge of history helped me understand the current political situation better. "

"South Africa has many goldmines."

"The student's venture into the unfamiliar subject of calculus was a risky one, but she persevered. "

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

"The geologist found a deposit of gold ore in the mountain, far from the surrounding rock. "

"She accumulated a plentiful collection of books."

"The family's stockpile of canned goods was enough to last them through the entire winter. "

"The lemonade stand was very profitable for the children, earning them enough money to buy a new game. "

"The sergeant major is a regular in the British Army. "

"The economic situation in the city has affected many families' ability to afford groceries. "

"I seek wisdom."

"I work in a medical research institute."