"是好事"在英语中可以用"it's a good thing"来表达。
这个表达是从中文翻译过来的，在英语中，"a good thing"表示一件好事或好的东西。
举个例子，你可以用这个表达来回答别人问你是否觉得某件事是好事：
Q: "Do you think it's a good thing that we're going to the beach today?"
A: "Yes, I think it's a good thing. The weather is nice and it'll be a fun day out."
翻译成中文就是：
Q: "你觉得今天我们去海滩是好事吗？"
A: "是的，我觉得是好事。天气很好，这会是一个有趣的出游。"
其他一些例子：
"It's a good thing that we have a backup plan in case something goes wrong." (这是好事，因为我们有备用计划以防出事。)
"It's a good thing that I packed some snacks for the road. I'm starving!" (这是好事，因为我带了些零食在路上吃。我饿死了！)
"It's a good thing that you called me before you made that decision. It could have had serious consequences." (这是好事，因为你在做出那个决定前打电话给我了。那个决定可能会造成严重的后果。)