Both the Japanese and Chinese languages have Chinese characters, which make it possible for Japanese students to understand Chinese. However, we also find that it is difficult for Japanese students to learn how to express thoughts and feelings in Chinese. This study presents the reasons for the problem and proposes methods to solve it. The effectiveness of the proposal is verified by two teaching experiments in the study. As is well known, the first foreign language of Japanese students is English. English is one of the most important subjects in junior and senior high school education, so, generally, Japanese students have enough experience in learning English. And, when learning a second foreign language, Chinese, they are unconsciously affected by English ways. When learning English, Japanese students have to cognitively process specific knowledge of vocabulary items and sentences (grammatical items) in order to understand the meaning of expressions. These provide necessary cognitive operations in the input processing (second language learning) models proposed by Vanpatten (1993, 1996) and Gass and Selinker (1994). The models demonstrate how learners process cognitively from input (language and knowledge about it) to output (language expression). Japanese students learn to express English with comparatively little special mental processing after having understood the language. Affected by the way of learning English, Japanese students do not pay much attention to expressive skills in Chinese when they understand the meanings in the language. These learning habits in Chinese cannot provide necessary processing in the input processing models which account for the processing way to grasp the second language. It is because, with knowledge of Chinese characters, Japanese students can understand the meanings in Chinese without learning vocabulary items and grammar. However, without specific knowledge of them, the students cannot learn how to express Chinese. How can we solve this problem? The way Japanese students learn Chinese is a habit transplanted from that of learning English, so it is an unconscious processing. To solve the problem, it is necessary to direct their attention to the necessary processing, specific knowledge on vocabulary items, and grammar. We propose that the teacher should train students to consider what Chinese expressions are in showing them the meanings in the language. The proposal is demonstrated to be correct by the results of experiments which show the students significantly improved their abilities to express Chinese words and phrases.