Conditional sentences are made of two clauses namely "if-clause" and "main clause". Conditionals have been noted by scholars and grammarians as a difficult area of English for both teachers and learners. The two clauses of conditional sentences and their form, tense and meaning could be considered the main difficulty of conditional sentences. In addition, some of non-native speakers do not have sufficient knowledge of the differences between conditional sentences in the two languages and they tried to solve their problems in their second language by using their native language. The aim of this study was to analyse the use of conditional sentences by Arab students of English in semantic and syntactic situations. For the purpose of this study, 20 Arab students took part in the questionnaire, they were all studying different subjects and degrees (bachelor, master and PhD) at Coventry University. The results showed that the use of type three conditionals and modality can be classified as the most difficult issues that students struggle to understand and use.