她警告他不要再赌钱了，因为已经输了很多。

She warned him not to ___gamble anymore because he had already lost a lot.

他冒险投资了这家初创公司，希望能获得高回报。

He decided to ___gamble on the startup, hoping for high returns.

他不该把全部薪水都赌在马赛上。

He shouldn't have ___gambled his whole salary on the horse race.