Make corrections of the given phrases where necessary.
If space technology (had been)  more advanced, humans could have settled in space decades ago. They could have founded colonies on other planets if natural conditions there had been suitable for sustaining life. People (could inhabit)  space stations there were not for the need to send regular and costly supply expeditions there. They (can)  be using mineral resources from space bodies if they (had not worked)  out a way to deliver the resources to Earth. If people (were less)  united on Earth, they would be more cooperative in space programmes and would have advanced a lot more in their achievements. We would have learned how to stop global warming. We (would have been stopping)  ozone windows from growing in the atmosphere decades earlier. We (would)  pollute the Earth with rubbish. Finally, we would consider the Earth our home.

If space technology were more advanced, humans could have settled in space decades ago. They could have founded colonies on other planets if the natural conditions there had been suitable for sustaining life. People could inhabit space stations if there was no need to send regular and costly supply expeditions there. They could be using mineral resources from space bodies if they had not worked out a way to deliver the resources to Earth. If people were less divided on Earth, they would be more cooperative in space programs and would have made a lot more advancements. We would have learned how to stop global warming. We would have been preventing ozone holes from growing in the atmosphere decades earlier. We wouldn't be polluting the Earth with rubbish. Finally, we would consider the Earth our home.