Before revision:  Overall, we have covered the task formulation, existing datasets and metrics for model development and evaluation , and all methods developed over the last several years. We reveal that existing methods are indeed based on a combination of several loss functions with each of which serving a certain goal. Such a unique perspective we provide could shed light on the design of new methods.
After revision:  Overall, we have covered the task formulation, existing datasets and subtasks, evaluation metrics, and methods on parallel and non-parallel data. We also provide discussions a variety of important topics regarding TST, which can shed light on the design of new methods.