He has long been engaged in the research and production of ultrasonic aer-mechanical ground testing equipment, and the theoretical and experimental research on strategic weapons and carrier rockets.是什么意思_He has long been engaged in the research and production of ultrasonic aer-mechanical ground testing equipment, and the theoretical and experimental research on strategic weapons and carrier rockets.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句