noun
BAD : I am taking another course to improve my qualification.
GOOD : I am taking another course to improve my qualifications.
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qualifications (plural) = the examination passes, skills and experience that you need for a particular job: 'I'd like to apply for the job but I don't have the right qualifications.'
qualification = a degree, diploma, certificate etc: 'Do you have a postgraduate qualification?' Speakers of American English use degree, diploma, certificate etc for this meaning.