| English has been the most familiar foreign language for Indonesian learners. They have learnt English since they were in elementary level. The learners have been taught about grammar, vocabulary, pronunciation, speaking listening, reading, and writing in English. Especially for grammar, learners have known the tenses from the very beginning level. The first five tenses that are taught for beginners are Simple Present Tense, Present Continuous Tense, Simple Past Tense, Past Continuous Tense, and Present Perfect Tense. Learners learn these five tenses from elementary to secondary level. The present study aims to find out what is the most problematic tense for students and why this tense becomes problematic to them. To obtain the data, the researcher used two methods, namely (i) Structure test consisting of fifty questions, and (ii) the interview. The results of the Structure test and the interview show that the most problematic tense for students enrolled in 2007 is Past Continuous Tense. This tense is difficult because they cannot distinguish it from Simple Past Tense, therefore, they use Simple Past Tense instead of Past Continuous one. They get influenced mostly from their workbook. For the students enrolled in 2005, the most problematic tense is Present Perfect Tense. Again, they get switched with Simple Past Tense because they do not understand the context clearly. Most of the students agree that time signal help them a lot in doing the Structure test. They also try to analyze the context to make the learning easier. The students get the biggest influence from their mother tongue and strategy of second language communication which always make them repeat the same mistakes. |