\[
\begin{array}{rl}
\hline 1 \, \text{kL} & = 10^{\boxed{3}} \, \text{L} \\
\hline 1 \, \text{dL} & = 10^{\boxed{-1}} \, \text{L} \\
\hline 1 \, \mu\text{L} & = 10^{\boxed{-6}} \, \text{L} \\
\hline 1 \, \text{nL} & = 10^{\square} \\
\hline
\end{array}
\]