source: As the 25th Brigade fell back, the right of the 23rd Brigade was exposed and enveloped by the Germans and the brigade retreated to avoid being rolled up.
target: The right of the 23rd Brigade was exposed as the 25th Brigade fell back. The right was enveloped by the Germans. The brigade retreated to avoid being rolled up.
references: The right of the 23rd Brigade was exposed as the 25th Brigade fell back. The right was enveloped by the Germans. The brigade retreated to avoid being rolled up.