Translations of figures preserve the lengths and angles of the original figures, then all the segments of the image figure are parallel to correspondant segments of the original figure.
Then you can state that the same relation between any two sides of the original figure is what you will have for the image.
AB is parallel to HE
AD is parallel to HG
DC is parallel to GF
BC is parallel to EF
Then is EF is parallel to HG in the pre-image the correspondant segments in the image are parallel too, i.e. BC is parallel to AD in the image.