/fəˈnɒmɪnən; US -nɒn ||; fəˈnɑməˌnɑn/noun
[C] (pluralphenomena /-ɪnə ||; -ənə/) a fact or an event in nature or society, especially one that is not fully understood 现象:
Acid rain is not a natural phenomenon. It is caused by pollution.酸雨不是自然现象,而是由污染造成的。