Generation of intense isolated attosecond pulses is of significant importance to explore new domains in attosecond science. Recently, we have demonstrated high-order harmonic generation (HHG) with high conversion efficiency using low-density plasma as the nonlinear medium [1,2], instead of gas. However, isolated attosecond pulses have yet to be demonstrated from plasma. In this work, we apply the Double Optical Gating (DOG) [3] method to generate continuum high-order harmonics from lowly ionized carbon plasma, which is the first step toward the generation of intense attosecond pulses.