7. As shown in the figure, the size relationship of $\angle 1, \angle 2, \angle 3$ is ( ).
(A) $\angle 2>\angle 1>\angle 3$.
(B) $\angle 1>\angle 3>\angle 2$.
(C) $\angle 3>\angle 2>\angle 1$.
(D) $\angle 1>\angle 2>\angle 3$.
Answer: D.
Solution: It is obvious that $\angle A O E=\angle 2$.
According to the exterior angle theorem of a triangle,
$$
\angle 1>\angle A O E=\angle 2>\angle 3 .
$$

Therefore, the answer is D.