shù : zhí > zhì zhōng jiān 
   zhì zhōng jiān ( replicativeintermediate) shì bìng suān zài zhì guò chéng zhōng chū xiàn de zhǒng jié gòu bān zài bìng yīn ssdna huò
  ssrna zhì shí xíng chéng dsdna huò dsrna, zhì guò chéng suǒ chǎn shēng de zhōng jiān fènzǐ ri( replicativeintermediate) - zhì zhōng jiān