speculation: n.1.沉思，思索，考虑。2.推测；空谈。3.投机，投机事业[买卖]。4.一种纸牌戏。短语和例子buy sth. as a speculation 投机购买某物。 engage in speculation 做投机生意。 much given to speculation 想入非非。 Much speculation is rife concerning [as to] .
A century ago , astronomers believed that they saw canals on mars through telescopes . this led to the speculation of existence of intelligent life or even fears of attacks from mars 一百年前的天文学家相信从望远镜观察到火星上有运河，不禁使人猜想到火星上是否存在有智慧生物，甚至引起火星人袭地球的疑云。
