What came next happened so fast no one saw how it happened — one second, Piers and Dudley were leaning right up close to the glass, the next, they had leapt back with howls of horror.
Harry sat up and gasped; the glass front of the boa constrictor’s tank had vanished. The great snake was uncoiling itself rapidly, slithering out onto the floor. People throughout the reptile house screamed and started running for the exits.
As the snake slid swiftly past him, Harry could have sworn a low, hissing voice said, “Brazil, here I come. … Thanksss, amigo.”
The keeper of the reptile house was in shock.
“But the glass,” he kept saying, “where did the glass go?”
What came next happened so fast no one saw how it happened —
what came next，what引導的名詞性從句，可以理解成什麼的事情或者什麼的東西，所以What came next的意思是接下來的這件事情。
Happened so fast和no one之間省略了that，happened so fast that no one表示發生得如此之快，如此迅速。
因此，全句是：接下來的事情發生得如此之快，以至於沒有人看到它是怎麼發生的。
one second, Piers and Dudley were leaning right up close to the glass, the next, they had leapt back with howls of horror.
這句話有兩個層次，第一層是one second怎麼樣，第二層是the next怎麼樣，因此one second不能理解成一秒，而是前一秒，the next有省略，應是the next second下一秒，二者表示前一秒發生了啥事，下一秒緊接著又發生了什麼事。
前一秒，他們一下子緊緊地貼在那扇玻璃上，下一秒這兩人就一邊驚恐地尖叫著，一邊往後跳。
leapt back往後一跳；with howls of horror發出驚恐的叫聲。
Harry sat up and gasped; the glass front of the boa constrictor’s tank had vanished.
Harry被撞得摔到地上，這個時候他坐了起來，倒抽一口冷氣：那隻巨蟒展箱正面的玻璃，have vanished消失不見了
The great snake was uncoiling itself rapidly, slithering out onto the floor.
這這條巨大的蛇正在uncoiling，什麼是uncoiling？
蛇把身體盤成一卷一卷的，那樣一卷/一盤叫作coil，所以uncoil就是將盤成一卷的東西展開，也就是這條蛇正在把盤成一卷的身體快速地展開，然後滑到外面的地板上。
這就不得了了，猛獸出籠！
People throughout the reptile house screamed and started running for the exits.
整個爬行展館裡面的人，他們尖叫著，開始向出口跑去。
As the snake slid swiftly past him, Harry could have sworn a low, hissing voice said, “Brazil, here I come. … Thanksss, amigo.”
當這條蛇輕快地劃過Harry身邊，Harry幾乎可以發誓自己聽到了有一個低沉的、嘶嘶嘶的聲音，說：“巴西，我來了。謝謝，amigo。” amigo不是英語單詞，是西班牙語，表示朋友。這條蛇重獲自由，然後說巴西老家，我來了，又對Hanry說，謝謝你啊，我的朋友。
這個就很有意思了，這條蛇還挺騷包，是條瀟灑的蛇。
The keeper of the reptile house was in shock.
爬行動物館的開門人簡直是震驚了。
“But the glass,” he kept saying, “where did the glass go?”
“但是那扇玻璃，那玻璃到底哪去了？”他不停地這樣問。
到底玻璃怎麼消失的？至少此刻沒有人知道。
小結
Hanry在動物園裡竟然跟一條蟒蛇看對眼，並且進行了溝通，達力和他的夥伴急匆匆跑過來，把哈利推倒在地，想看蟒蛇的時候，關著這條蟒蛇的櫥窗玻璃就神秘消失了，沒有人知道是怎麼回事。
哈利波特與魔法石英文原著精讀筆記2-09
哈利波特與魔法石英文原著精讀筆記2-10
哈利波特與魔法石英文原著精讀筆記2-11
哈利波特與魔法石英文原著精讀筆記2-12
哈利波特與魔法石英文原著精讀筆記2-13