To find the fraction that represents the section of fence George can build per hour, we start with the information given:
George builds \(\frac{1}{331}\) section of fence every \(\frac{1}{221}\) hour.
To determine how many sections he can build in one hour, we can set up the equation:
\[ \text{Sections per hour} = \frac{\text{Sections built}}{\text{Time taken}} = \frac{\frac{1}{331}}{\frac{1}{221}}. \]
Dividing by a fraction is the same as multiplying by its reciprocal, so we can rewrite the equation as follows:
\[ \text{Sections per hour} = \frac{1}{331} \times \frac{221}{1} = \frac{221}{331}. \]
Therefore, the fraction that represents the section of fence George can build per hour is
\[ \frac{221}{331}. \]