This paper retrospects to the developing history and usage status of radioisotope thermoelectric generator (RTG) used in space in the 20th century.是什么意思_This paper retrospects to the developing history and usage status of radioisotope thermoelectric generator (RTG) used in space in the 20th century.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句