关于in the past/last few years的句型转换！

关于in the past/last few years的句型转换！
句型转换
In the past thirty years,many laws have been passed to take away our rights and stop our development.
____ ____ ____ ____ ____ ____the greatest number of laws stopping our rights and progress.
（答案： The last thirty years have seen
请问可以换成the past thirty years have seen么 二者有何区别？）