Breaking into pieces is a process of causing something to fragment or shatter into several small parts. The antonyms for this phrase could be assembling, gathering, or consolidating. When something is assembled, it means it is put together, rather than being broken apart. Gathering is also an antonym because it means to collect and bring things closer, rather than dispersing them. Consolidating, on the other hand, refers to the process of combining items into a single, cohesive unit, rather than breaking them apart. In essence, the antonyms for breaking into pieces revolve around keeping things together, rather than breaking them apart.