mini還是全文聽(tīng)寫模式，很多童鞋可能進(jìn)來(lái)看到【專八】可能會(huì)有點(diǎn)膽怯，剛開(kāi)始是會(huì)感覺(jué)到有點(diǎn)吃力哦，但這就是專八。希望大家可以耐心的認(rèn)真聽(tīng)寫O(∩_∩)O~
In fact, the collapse played out just like a controlled demolition. To destroy a building, experts usually place explosives not just on the lowest three floors, but also on higher floors. With the top floors exploding, demolition experts can create what they call a "pancake effect", which you might realize is the same as a downward domino-effect. Unlike dominos, of course, the towers fell straight down rather than sideways. But their downfall was caused by the same forces that knock a line of dominos on their faces : Floors on the top gave in, crashing through the floors below them. As each concrete floor fell, it added force to the collapse - making it harder for each floor to hold up against the increasing pressure. Once the top floors gave way, the rest of the catastrophe was inevitable.