Oil prices are especially volatile, as the large swings over the last five years remind us. The recent oil boom could easily turn to bust, especially if global economic activity slows.
油价波动特别厉害，最近五年的过山车走势是一个很好的提醒。近期的石油大牛市很容易逆转成熊市，尤其是当全球经济活动减速。