Those previous works on combining TM and SMT can be classified into four categories: (1) selecting the better translation sentence from TM and SMT (He et al., 2010a;2010b;Dara et al., 2013); (2) incorporating TM matched sub-segments into SMT in a pipelined manner (Koehn and Senellart, 2010;; (3) only enhancing the SMT phrase table with new TM phrase-pairs (Biç ici and Dymetman, 2008;Simard and Isabelle, 2009); and (4) incorporating the associated TM information with each source phrase to guide the SMT decoding .
all previous works mentioned above only focus on the case in which the TM database and the SMT training set share the same data-set.