1.沉思,思索,考虑(about, on, upon):This is the method that we have been speculating about.这正是我们一直在思考的方法。2.推测,猜测 (about,on):No one can speculate on what he's thinking about.没人知道他在想什么。3.做投机生意;投机:to speculate on the futures搞期货投机生意vt.