[经] deferred research and development

dì yán yán jiū yǔ fā zhǎn chéng běn ㄉㄧˋ ㄧㄢˊ ㄧㄢˊ ㄐㄧㄡ ㄩˇ ㄈㄚ ㄓㄢˇ ㄔㄥˊ ㄅㄣˇ