锻炼是保持健康的最可靠方法。

Exercise is the ___surest way to stay healthy.

在所有队员中，他对这场比赛的结果最有把握。

Among all the team members, he was the ___surest about the outcome of this match.

定期锻炼是保持健康最可靠的方法。

Regular exercise is the ___surest way to maintain good health.