按照“海恩法则”,一起严重事故的背后,有着几十起甚至上百起轻微事故或未遂事故。今年不断出现的高铁事故,已暴露铁路运行存在的种种问题。而如果足够重视,或能避免事故的发生。这说明①矛盾是对立统一的 ②事物的变化发展是内外因共同作用的结果③事物的变化发展是量变与质变的统一 ④事物发展是前进性和曲折性的统一
The firemen ____the fire as soon as they got to burning buildings.
Has he ever been heard __about his trip to the lonely island?
Children can play “trick or treat” games on ____in western countries.
It’s _____ unusual day for him to get ______ useful stationery.
—Look at the sign. It says “No Parking”. ----.