The discloses a method and device in a user equipment and a base station for wireless communication. The user equipment receives a first signaling, wherein the first signaling is used to determine a first time-frequency resource group, and the first time-frequency resource group is reserved for a first bit block; receives a second signaling, wherein the second signaling is used to determine a second time-frequency resource group, and the second time-frequency resource group is reserved for a second bit block; and transmits the first bit block and the second bit block in the second time-frequency resource group, or transmits only the second bit block. Time domain resource(s) occupied by the first time-frequency resource group and the second time-frequency resource group are non-orthogonal; a timing relationship between the first signaling and the second signaling is used to determine whether the first bit block is transmitted in the second time-frequency resource group.