4   chunking errors affect the translation quality, we removed extremely long chunks from the training data.
among the 2 million preprocessed translation pairs, we excluded sentence pairs that matched any of following conditions: (1) The length of the source sentence or target sentence is larger than 64 (3% of whole data); 2The maximum length of a chunk in the target sentence is larger than 8 (14% of whole data); and 3The maximum number of chunks in the target sentence is larger than 20 (3% of whole data).