In the recent years, more and more cosmologists began to search for heavy field imprints during inflation. Traditionally, these heavy fields decay very quickly after horizon crossing and thus its contribution to the power spectrum of curvature perturbation and gravitational waves can be neglected. In this talk, however, I will focus on the heavy scalar fields which shows resonant behaviour inside Hubble horizon. Then both of their nonlinear corrections to curvature perturbation and GWs cannot be ignored, which breaks the well-known Lyth bound and has unique imprints on CMB B-mode.