幸亏的英语短文怎么说

"Fortunately" or "luckily" are both good ways to translate "幸亏" in English. You could use either one in a sentence like "幸亏我们提前准备了伞，否则我们就被雨淋湿了" (Fortunately, we had prepared an umbrella beforehand, or else we would have gotten wet in the rain).
Here is an example of how you could use "luckily" in a sentence: "幸亏我们及时到达了机场，否则我们就错过了航班" (Luckily, we arrived at the airport on time, or else we would have missed our flight).
"Fortunately" can also be used in this context: "幸亏我们没有遇到交通堵塞，否则我们就迟到了" (Fortunately, we didn't encounter any traffic jams, or else we would have been late).