A novel terahertz plasmon induced transparency (PIT) metamaterial structure consisting of single-layered graphene microstructures is proposed and numerically studied in this paper. A pronounced transparency peak is obtained in the transmission spectrum resulting from the destructive interference between the graphene dipole and monopole antennas. Further investigations have shown that the spectral location and lineshape of the transparency peak can be dynamically controlled by tuning the Fermi level in graphene. Since the monopole antennas in our designed structure exist in a continuous form, it is much more convenient to realize the tunablity by applying a gate voltage than those structures with discrete graphene patterns. This work may open up new avenue for designing tunable terahertz functional devices and slow light devices.