有空做某事英语短语怎么说

If you want to say that you have some free time and want to do something, you can say "I have some time on my hands and I want to do something." If you want to be more specific about what you want to do, you can say something like "I have some free time and I want to do some shopping" or "I have some time to kill and I want to go for a walk."