a retroactive law的用法和样例：
- The ratification has a retroactive effect, the same as the previous command.
- So it is like a retroactive decision then? I mean I could forget about her. And then when she comes back. Act like I just pretended to forget about her.
- For assets purchased before the date of issuance of the aforementioned Notice, a retroactive adjustment is not required if the residual value is less than 5%.
- A true scientific law admits of no exception.
- Such a death sentence is bad law.