The fact that the unchanging regions are so conserved over the course of evolutionary time means that they perform vital roles and that the virus cannot let them change without perishing.是什么意思_The fact that the unchanging regions are so conserved over the course of evolutionary time means that they perform vital roles and that the virus cannot let them change without perishing.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句