There are many reasons why somebody would want to certify their level of English: studying abroad, looking for a better job, getting a work promotion, just to mention some. There is a variety of exams available for certifying it. There is not one that is better than the others. Your choice must depend on your purpose, since they also have different features. In the case of Cambridge English exams, unlike other ones like TOEIC or TOEFL, there is a specific exam for each CEFR level. Hence, you would have to choose the right one for the level you want to certify. However, they have the advantage of not expiring, which can make it more appealing than other options.
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