We're reading an adventure story about piracy on the high seas.我们正在读一篇公海海盗的历险故事。He headed northeast across the open sea.他向那片公海的东北方向行进。A storm started up once we got out into the open ocean.我们一进入公海就下起了暴风雨。The fishing boats headed for the open sea.渔船向公海驶去。