重點講解：
1. be discharged from 允許…離開(醫院、軍隊)；
When he was discharged from the hospital, he had lost 20 pounds.
出院的時候，他的體重減輕了20磅。
2. attribute to 把…歸因于；把…歸咎于；
The coach attributed the team's victory to training and practice.
教練把球隊的勝利歸功于平時的訓練。
3. set off 動身；出發；啟程；
We set off in a southerly direction.
我們向南出發了。
4. ahead of 早于；在…之前；
And its monetary-policy arm's overstimulative policy ahead of the credit boom arguably made it a stoker of systemic risk.
而美聯儲貨幣政策部門在信貸極度擴張之前實施的過度刺激經濟的政策對系統性風險起到了推波助瀾的作用。