Let G X be a topological action of a topological semigroup G on a compact metric space X. We show in this paper that for any given point x in X, the following two properties that both approximate to periodicity are equivalent to each other: • For any neighborhood U of x, the return times set {g ∈ G : gx ∈ U } is syndetic of Furstenburg in G. • Given any ε > 0, there exists a finite subset K of G such that for each g in G, the ε-neighborhood of the orbit-arc K[gx] contains the entire orbit G[x]. This is a generalization of a classical theorem of Birkhoff for the case where G = R or Z. In addition, a counterexample is constructed to this statement, while X is merely a complete but not locally compact metric space.