Current thinking about how spiral galaxies form trac es back to an idea nearly 2 millennia old, to 2nd-century Egyptian mathematician Ptolemy.是什么意思_Current thinking about how spiral galaxies form trac es back to an idea nearly 2 millennia old, to 2nd-century Egyptian mathematician Ptolemy.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句