It’s been a long time since I’ve had cheesecake.
It's been raining non-stop for three days. - It has been raining nonstop for three days.
It's been raining non-stop for three days.
It has been raining nonstop for three days.
It's never been done before. - It has never been done before.
It's never been done before.
It has never been done before.
... that has halted the progress Iran's nuclear program ...
... it has dropped in the past, the medium projection of the U.N. Population Division is that population ...