22. In $\triangle A B C$, $E$ is a point on side $A B$, $A E$ $=1, E B=2$. If points $D, F$ are on sides $A C, B C$ respectively, and $D E / / B C, E F / / A C$, then the ratio of the area of quadrilateral $C D E F$ to $\triangle A B C$ is ( ).
(A) $4: 9$
(B) $1: 2$
(C) $5: 9$
(D) $3: 5$
(E) $2: 3$
22. A.

From similarity, $S_{\triangle A D E}=\frac{1}{9} S_{\triangle A B C}$.
Similarly, $S_{\triangle B E F}=\frac{4}{9} S_{\triangle A B C}$.
Therefore, $S_{\text {quadrilateral } C D E F}=S_{\triangle A B C}-S_{\triangle A D E}-S_{\triangle B E F}$ $=\frac{4}{9} S_{\triangle A B C}$.