「罪魁禍首」

(pos:名詞)
yue:領導或策劃犯罪嘅首要人物（量詞：個）
eng:chief culprit or criminal
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<explanation>
yue:引申指事件嘅主因
eng:figuratively, the chief cause
<eg>
yue:佢鼻敏感咗三十年，最近先至發覺原來罪魁禍首係花粉。 (keoi5 bei6 man5 gam2 zo2 saam1 sap6 nin4, zeoi3 gan6 sin1 zi3 faat3 gok3 jyun4 loi4 zeoi6 fui1 wo6 sau2 hai6 faa1 fan2.)
eng:He has nasal allergy for 30 years, but he has just recently discovered that the chief cause is pollen.