a shark's dorsal fin的用法和样例：
- The shark's dorsal fin was cut off by the fisherman.
- The shark's dorsal fin was cut offby the fisherman.
- His dorsal fin was down and his huge pectorals were spread wide.
- The dorsal fin is ornamented with these two colours.
- The second dorsal fin, near the tail, is much smaller.
- Full pearls below the dorsal fin area cum golden brush on the tail makes this a High Grade Bukit Merah Blue brooder.