Keyword: Errors, The Simple Present Tense and The Simple Past Tense The main purpose of this thesis is to study students’ errors in changing sentences using the simple present tense into sentences using the simple past tense in the seventh grade at SMP Negeri 1 Bulakamba Brebes in Academic Year 2012/2013. The population of this study is all of the seventh grade students of SMP Negeri 1 Bu…