A great deal of L2 vocabulary is indeed learned through extensive reading,which could contribute to solving the beginner's paradox.In extensive reading,the vast majority of vocabulary can be learned gradually through repeated exposures in various discourse contexts.Direct instruction of vocabulary cannot possibly account for the vast growth of students'vocabulary.Consequendy,teachers should promote extensive reading because it can lead to greater vocabulary growth than any program of explicit instruction alone ever could.Make sure that students should be preoccupied with relevant background knowledge and have great interest in chosen materials.In this paper,the technique of semi-extensive reading is also developed to help learners balance contextual guessing with dictionary use.Furthermore,at the end of this paper,some pedagogical implications are also given.