Design and implementation of a THz-TDS system working in both transmission and reflection modes with continuously varying incident angles,while the samples are kept in situ,are presented.Switching between the two working modes just needs to flip a single mirror in the measurement beam path.The system provides great feasibility and versatility to measure the full electromagnetic (EM) responses of samples,especially for the family of metamaterials which could posses a chiral or bianisotropic responses to the incident EM fields and a single transmission or reflection measurement is not sufficient to effectively extract the sample's response.The issue of data extraction is discussed in this presentation,which is not trivial in the situation when reflection measurements are involved because of the always standing phase uncertainty.The results from different measurement schemes and data processing methods are valued.