@mhmmdkashif:- Brother the amnesia in your case is not becos of lack of words, but ideas. be engaged in varied reading, try noting important points such as specific arguments, details, concept maps.
i would like to share a word on improving vocabulary. i believe that words are just like pegs of ideas. now keep your subjects in view and read time ang again its glossary of words, these are the words u will need the most while attempting paper. u should have ample words relating to sociology[if u opt this subject] likewise with other papers. extensively read newspaper for current affair vocabulary, diction, arrangment.. however do not get OVER RUN by number of words.go for ideas, and words will naturally flow to you.
Afterall the piece you r reading now is only a collection of ideas[suggestions etc] but it is knit in ideas!
it doesnt mean that u become totally carefree. It is essential to work on grammatical structure ,reason is that your english should be understood sentence by sentence, but it should retain structurly forceful arrangment.for this i would recommend you to read TOEFL, read model language. it is, according to my estimations, easy way of avoiding common mistakes in grammar.
secondly, do not think that lack of words was the only reason for your failure [in 2007] there could be other reasons try to sort out those.practise past papers, have them checked by a proffesional in his field, also by a css qualifer,if possible.


wish u success in upcoming exam.

regards
dr.g.asghar

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There are only four questions of value in life, Don Octavio: What is sacred? Of what is spirit made? What is worth living for? What is worth dying for? The answer to each is only love."
Don Juan DeMarco(Johnny Depp), in Don Juan DeMarco