【Solution】Solution: According to the problem, we know:
The number 6 must be filled in last.
First, analyze $A$. If it is the number 2, the next step would be $C$, but $C$ cannot be 1, 2, 3, or 4; it can only be 5. Then, moving to $B$, filling in 3 would end the sequence, which does not meet the problem's requirements.
If $A$ is 3, the next step would be $D$, which can be 4 or 5. If it is 4, the next step would be $B$, and the sequence cannot continue. If $D$ is 5, the sequence still cannot proceed to 6.
If $A$ is 4, the next step would be $E$, which can be 3 or 5. If it is 5, the sequence still cannot reach 6. Therefore, $E$ must be 3. The next step is $B$, which can be 2, and $D$ can be 5, completing the sequence with $C$ as 6. Therefore, the answer is: 42653.
11. (12 points) As shown in the figure, there are 6 circles on a ring. If you start filling in the numbers $1 \sim 6$ from the circle marked $S$, the number you fill in determines how many circles you move clockwise to fill in the next number (this number can be filled in arbitrarily). If all numbers from 1 to 6 can be filled in exactly, it is called a complete ring. The figure shown is one way to fill in a complete ring. Please complete the given complete ring, and the 5-digit number $A B C D E$ is $\qquad$.

