1.   But in recent decades the sea walls built behind the marshes as a secondary defence have been blocking their retreat and have squeezed them.

2.   Sharpened stakes placed by the English forced the French into a funnel that blocked their retreat.

3.   Another group of guards and several inmates chasing after the fleeing prisoners blocked their retreat.

4.   Just then the other ranger backed his jeep, effectively blocking our retreat.

5.   The Taliban fighters became trapped by the Shiites and Uzbek soldiers who blocked their retreat.

6.   The Taliban became trapped by the Shiites and Uzbek soldiers who blocked their retreat.