\item \self Translate the following sentences into predicate logic. Be as precise as possible. Give the meaning of any function and predicate symbols you use.

\begin{enumerate}
  \item Nobody knows everybody.
  \item All birds can fly, except for penguins and ostrichs.
  \item Not all birds can fly, but some birds can fly.
  \item All kids are cute and quite if and only if they are sleeping
\end{enumerate}