Abstract:
The main purpose of this study was to analyze the common grammatical errors committed by students' written sentences ,specifically at Kersa Secondary School students .It was attempted to analyze the activities for various purposes ;such as a) to analyze the common grammatical errors committed by students b)to examine their causes .The subjects of the study were 54students selected by using stratified sampling technique. The data was collected through document (text)analysis of students' written sentences. The collected data were then analyzed by classifying ,identifying, quantifying ,and analyzing the errors committed .After analyzing al l of the data ,the researcher found out that 390errors which contained 40.77%tense verb errors ,11.7%prepositioerrors,7.94% and pronoun errors .From the findings it can be concluded that the most common grammatical errors in the writings of grade ten students are :tense verb ,preposition and pronoun. Furthermore the researcher found out that178mechanic errors .Among these errors punctuation holds 46.62%as the main writing difficulties of the students .Accordingly ,it is finally revealed that the main source behind students 'errors is itralingual with high percentage ;then followed by interlingual transfer with low percentage .Consequently, teachers should engage their students in composition writing regularly .Concerted efforts should be taken in the appointment of qualified and well motivated language teachers
