Abstract: Different from most flare studies based on observations in the optical band, this paper focuses on the elementary units of solar activity——flaring loops and physical parameters that vary in time and space, as observed by radio microwave (cm band) spectra and images. In particular, this paper will be an important reference for studies on the data collected by a new radio heliograph (MUSER) built in China, which has the highest time, space, and frequency resolutions to date. In addition, X-ray, EUV, and optical studies related to microwave emission are included, in accordance with the trend of multiple wavelength research in all the various fields of astrophysics, including solar physics. Only the most representative studies, the ideas, main conclusions and typical figures are mentioned; for detailed data analysis and theoretical derivations, readers can look up the original references.