Then, Model-1 and Model-2 are employed to decode the input sentences x 2 and x 1 , resulting in pseudo training data (x 2 , y 1 ) and (x 1 , y 2 ), respectively.
we can obtain the triple parallel training data D = (x 1 , y 1 , y 2 ) ∪ (x 2 , y 1 , y 2 ) , which can be used to train our synchronous translation model mentioned above.