How to teach and learn English vocabularyAs is widely known, vocabulary, the building material, is essential to a language. It is one of the three basic components (pronunciation, vocabulary and grammar), and is of utmost importance to peoples communication and language learning. Language emerges first as words, and the coining of new words never stops. Pronunciation and grammar are presented by vocabulary. The linguist David Wilkins (1972) once summed up the importance of vocabulary in his book Linguistics and Language Teaching: Without grammar very little can be conveyed, without vocabulary nothing can be conveyed. According to Hocking D, spending most of ones time on words and expressions rather than grammar will improve ones English very much. Without enough words one cannot communicate with others, no matter how wonderful his grammar and pronunciation are (McCarthy, 1990), because vocabulary is the carrier for people to communicate with each other. To achieve the purpose of communication, people need to learn vocabulary first. Words enable people to speak, read and write with clarity, confidence and charm. Furthermore, to learn a new language is to some degree to build a new network, which is expressed by vocabulary. These lead to the fact that vocabulary forms the very backbone and essence of any language. Therefore, acquiring adequate vocabulary is of critical importance to language learners. It is clear enough that without a knowledge of words, language learning will turn out to be a castle in the air. Generally speaking, the vocabulary that a learner owns most conspicuously reflects his or her English level, which infers that, to master a language, a large vocabulary is necessary and it is very important for learners to memorize a great many English words. Therefore, the importance of vocabulary establishes it a basic and crucial position in language teaching and learning. Scholars represented by Lewis (1993) even put forward that vocabulary should be the center of language teaching and learning.1 Need for a specific required vocabulary in senior high schools in ChinaSince vocabulary plays a basic role in language, to some degree, it is necessary for learners to acquire adequate vocabulary. Vocabulary size is an important criterion to measure ones English proficiency. The larger ones vocabulary size is, the better his English is. More words mean more freedom in language use. Without a certain vocabulary size, the training of language skills turns out to be a tree without a root. Therefore, it is not grammar or syntax but vocabulary that makes it difficult to master a language. So, how many words should Chinese senior students need to master in order to have a good comment of a language? Laufers experiment of the threshold vocabulary suggests that the turning point of vocabulary size for effective reading comprehension is about 3,000 word families (approximately 5,000 words). Most researchers found that a large vocabulary will provide a good lexical coverage of a text: 1,000 frequent words cover 80.5% of a text; 2,000 words cover 89%; 3,000 words cover 93%; 4,000 words cover 95% and 5,000 words cover 97% (Wang Rongpei, 1997: 3). The higher the coverage is, the lower the density of unknown words is. In China, we have revised or adjusted the English syllabus for almost every ten years since 1948. It is suggested that, when senior students graduate from school, they should master an English vocabulary as follows: 1948- 6,000 words, 1951 - 5,000 words, 1963, - 3,500-4,000 words. 1978, -2,200words. 1986, -1,800-2,000 words, 1992, -1,200 words (and 800 more words), 2001,- 3,000 words (and 400-500 idioms or collocations) (Huang Jianbin, Wang Li, etc., 2003)The decreasing number of English words from 6,000 to 3,000 indicates lowering difficulty in vocabulary learning, which misleads vocabulary teaching and learning. As mentioned above, the lowest 1,200 words are not enough for senior students. Vocabulary threshold is 2,000 to make communication possible. Fortunately, in 2001, a new vocabulary criterion Senior English Curriculum Criterion in China (Experiment Edition, 2001) is proposed as more attention is paid to the essence of vocabulary. The purpose of senior vocabulary teaching is mentioned that students should know the meanings and the use of 3,000 words and 400-500 idioms or collocations; scientific and effective vocabulary learning strategies, especially vocabulary memorization strategies, are emphasized; students should also learn how to guess word meanings in context so that they can enlarge their vocabulary, distinguish word meanings and improve their ability of vocabulary learning. Therefore, it is most important for Chinese senior students to acquire adequate vocabulary.2 The current situation of vocabulary teaching and learning in senior high schools in ChinaNowadays vocabulary teaching is playing a fundamentally important and active role i