speculate

/ˈspɛkjəˌleɪt/

to believe especially on uncertain or tentative grounds

中文释义：推测；猜测；投机

Scientists speculate that the planet may have once supported life.

科学家推测这颗行星可能曾经存在生命。

Investors often speculate on the stock market to make quick profits.

投资者经常在股票市场上投机以快速获利。