When big cargo ships are traveling in ballast,that is,without any cargo,they often carry tanks of water in their holes to make them sink far enough into the water to be stable.是什么意思_When big cargo ships are traveling in ballast,that is,without any cargo,they often carry tanks of water in their holes to make them sink far enough into the water to be stable.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句