无火不生烟无风不起浪: there is no smoke without fire and there are no waves without wind
必: Ⅰ副词(必定; 必然) certainly; necessarily; surely 短语和例子必死无疑 be certain to die; 未必 can not be sure; 战则必胜 surely win the battle if fighting; 骄兵必败。 an army swollen with pride is bound to lose.Ⅱ动词(必须
