For most people, the importance of vocabulary seems very clear. We can communicate together by using incorrect grammatical patterns or imperfect pronunciation, but people will encounter difficulty in understanding what the interlocutors are saying and the communication may break down because they do not use the correct words. My students in Vietnam were also in the same situation. They did not use correct words in writing and speaking to express their ideas. The problem is that in English, there are many words whose meanings are related closely each other. The students at that time did not how to choose the words suitably in particular situation. To avoid this, in my teaching, I usually teach new words in contexts and recycle new vocabularies very often in different types of exercises. In production stage, I let the students talk to their peers freely but I finally corrected the use of word choice that the students made mistakes in front of the class and noticed them the meanings of the words when they occurred in a new context. This method has brought positive effect in my teaching. It helps my students improve the situation better.