The interaction of light and matter can induce many strange quantum optical phenomena, in which EIT and EIA are the most typical ones. In this paper, a radio-frequency field is introduced between two hyperfine levels of the excited state into a well-studied lambda three level system to form a modified quasi-lambda four level system consisting of an optical-radio two-photon coupling field and a probing field. Both EIT and EIA can be obtained in this system. By discussing the quantum coherence process after the optical-radio field is turned on until the system is stable, the generation and transformation of EIT and EIA during this period of time are analyzed, which is helpful to probe the correlation between two phenomena and to seek the method to regulate and control them.