gamemaster Fair enough. I was a bit tired when replying and missed that.
The lever on B will extend Bridge 9. Bridges 14, 13 and 10 should be extended already, so make your way to E via them. Pull the bottom lever at E to extend Bridge 4 if it isn't already extended. Cross to A and pull the lever there to extend Bridge 1 if it isn't already extended. Cross to B and pull the lever to extend Bridge 9. Make your way back the way you came.