14. Given that the weights of $A$, $B$, $C$, and $D$ are all integers in kilograms, where $A$ is the lightest, followed by $B$, $C$, and $D$, the weights of each pair of them are as follows (unit: kg):
$45,49,54,55,60,64$.
Then the weight of $D$ is $\qquad$ kg.
14.35.

Since $A+B=45, A+C=49, B+D=60, C+D$ $=64$, therefore, $C-B=4$.
Then $B+C=B+(B+4)=2B+4$ is an even number.
Among $54 \text{~kg}$ and $55 \text{~kg}$, only 54 is an even number, so $B=25$. Then $D=35$.