Standing at the betting window, Jacob tried to decide upon which horse to speculate -- when suddenly, he decided to bet on Gray Mare.
I speculate that this question is a homework assignment, but I could be wrong.
Speculate is a verb meaning "to form a theory or conjecture about something without firm evidence" "Even though I don't have any proof, I speculate she's trying to kill me."
Charles Goodnight was a great speculator who created a huge cattle ranching business.
it is interesting to remember that we still speculate about other planets