So complete was this adaptation that the gills of a tuna operate only when the fish is moving;
(So complete; was; this adaptation that the gills of a tuna operate) (the gills of a tuna; operate; T:only when the fish is moving) (the fish; is moving; )
So complete the gills of a tuna the fish
was operate is moving
this adaptation that the gills of a tuna operate
T:only when the fish is moving