根据以下内容，回答下列各题。 What do we mean____21____a perfect English pronunciation？In one sense there are asmany different kinds of English as there are speakers of it．___22___ two speakers speak in exactly the same way．We can always hear differences ___23___ them，and the pronunciation of Englis hvaries a great deal in different geographical___ 24___．How do we decide what sort of English touse___25___a model？This is not a question that can be____26____ in the same way for all foreign learners of English．When you live in a part of the world like India or West Africa,___27___there is a long ____28____of speaking English ___29___ general communication purposes，you should ___30___ to acquire a good variety of the pronunciation of this area．It would be a fashion in thesecircumstallces to use as a model BBC English or ___31___ of the sort．___32___ the other hand，if you live in a countly ___ 33___there is no traditional use of English，you must take as your model some form. of native English pronunciation．ItDoes not___34___very much which form. you choose .The most____35____ way is to take as your model the sort of English you can hear most often．

A. by
B. for
C. with
D. in