We describe a method for generating sentences from "keywords" or "headwords". This method consists of two main parts, candidate-text construction and evaluation. The construction part generates text sentences in the form of dependency trees by using complementary information to replace information that is missing because of a "knowledge gap" and other missing function words to generate natural text sentences based on a particular monolingual corpus. The evaluation part consists of a model for generating an appropriate text when given keywords. This model considers not only word n-gram information, but also dependency information between words. Furthermore, it considers both string information and morphological information.