Explain why the following two structures,$I$ and $II$,cannot be the major contributors to the real structure of $CH_{3}COOCH_{3}$.
$I: CH_{3}-C^{+}(O^{-})-OCH_{3}$
$II: CH_{3}-C(=O^{-})-OCH_{3}^{+}$

(N/A) The two structures are less important contributors because they involve charge separation,which requires energy.
In structure $I$,the central carbon atom has only $6$ electrons in its valence shell,meaning it has an incomplete octet.
In structure $II$,the oxygen atom is bonded to three groups and carries a positive charge,which is less stable due to the high electronegativity of oxygen.