题目内容：
WhatwastheachievementoftheEUproject? A．Itfoundotherchemicalmechanismsplayedacriticalrole.
B．Itfoundthedestructioncausedbychlorineplayedacriticalrole.
C．Itsuccessfullyhelpedreducetheemissionofchlorine,
D．Itsuccessfullyansweredalltheunsolvedquestionsaboutozoneloss.
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答案解析：