[ + to infinitive ] You're very fortunate to have found such a nice house. 你能找到这么一栋漂亮的房子真是非常幸运。
He was fortunate in his choice of assistant. 他很幸运,选择了一位好助手。
[ + that ] It was fortunate that they had set out early because the traffic was terrible. 幸运的是他们出发得很早,因为交通状况实在太糟了。
Opposite: unfortunate