speculate/speculation/speculative

speculate /ˈspekjuleit/ vi. & vt. 1. 推测，推断(about, on;作 vt.时跟从句)：speculate about one’s motive 推测某人的动机；speculate on one’s future 思索某人的前程 I was just speculating that this might be my last chance. 我刚认定这很可能是我最后一次机会。［考句］ Already the class is speculating about who our new teacher will be. 班上已经在推测新的老师是谁。2.投机，做投机买卖: speculate in stocks (gold mines) 做股票(金矿)投机

speculation n. 思索；做投机买卖：［考句］The speculations of finding gold in California attracted a lot of people to settle down there. 加州的淘金投机吸引了很多人到那里落户。

speculative /ˈspekjulətiv, -leit-/ adj. 1. 思考的，思索的，推测出的：speculative rumours仅属推测的谣言  2. 投机的，投机生意的：speculative market投机市场 The boss has put all his money into that speculative enterprise.这个老板把他的全部财产都投到那个投机事业中。