Remember the ownership pattern in different economic systems:
\[
\boxed{
\begin{aligned}
\text{Primitive Community} &\rightarrow \text{Common ownership},
\text{Slavery} &\rightarrow \text{Slave owners own land and slaves},
\text{Feudalism} &\rightarrow \text{Land owned by feudal lords},
\text{Capitalism} &\rightarrow \text{Private ownership and production for exchange}.
\end{aligned}
}
\]
Mnemonic: Primitive--Common, Slavery--Owners, Feudalism--Landlords, Capitalism--Market.