This paper aims to identify the topics and issues for further exploration in machine translation research. In order to provide insights into numerous challenges machine translation poses, this study analyzed a significant number of research papers published aborad and presented fifteen research topics. They include: post-editing productivity, post-editing vs. traditional human translation, post-editing efforts, process-oriented research, correlations between productivity and quality, translation memory vs. machine translation, post-editing rates, design of post-editing interface, variables affecting the quality of machine translation, the impact of linguistic elements of source text, automated machine translation evaluation, role of post-editors, post-editing in translator training, educational academia-industry cooperation. Among them, four research topics were selected for detailed discussion about the difficulties faced by translators and researchers at home and aborad.