The authorities have improved the public transport system recently. (improvements) The authorities _{……………………………………………………………..………}the public transport system recently.

The authorities have improved the public transport system recently. (improvements)

The authorities _{……………………………………………………………..………}the public transport system recently.

The authorities have improved the public transport system recently. (improvements) The authorities ……………………………………………………………..………the public transport system recently.