Original: Since the 1990s, significant investment has taken place to all blocks in Sheffield, and millions of pounds have been spent on measures that minimise fire risk.
Simplified: Since the 1990s, significant investment has happened to all blocks in Sheffield, and millions of pounds have been spent on measures that minimise fire risk.
Simplified: Since the 1990s, significant investment has been made to all blocks in Sheffield, and millions of pounds have been spent on measures that minimise fire risk.
Simplified: Since the 1990s, a lot of investment has taken place to all blocks in Sheffield, and millions of pounds have been spent on solutions that minimise fire risk.