The the s i s is a contrastive study of the auxi liary in Amharicrnand English, usinG TG model.rnIn the study, the s urface a nd deep structures of the a uxiliaryrnin Amharic and English h a ve been described a nd analysed separately.rnThe n , the surface structure contrast and the deep to surface structurerncontrast of the two l anguages h ave been inv estigated.rnOn the basis of this contrastive analysis it his been foundrnthat the constituent s of the a uxiliary in English (i.e., Tense ,rnModa l and Aspec t) are systematically different from the constituentsrnof tho a uxiliary in Am h ar ic (i. e ., Aspect , Moda l a nd Tense) evenrnin this order. Based on the result of th is comparison , hypothetica1rnpredictions of e rrors have been made which may be committed byrnAmhar ic s p eakers in learning the auxiliary i n EnGli sh.rnFinally, p a ttern practice based on the genera tive and tra nsformtrni onal rules discuss ed in the st u d y has b een recomm e n ded as arnmethod of overcoming the predicted e rrors .