Direction: The given sentence contains a blank. Identify the phrase/statement that can make the given sentence grammatically and contextually correct.
The underground drainage, especially in the vulnerable low-lying areas of this region, _________________________ the dry seasons of winter and summer.
1
ought to have improved during
2
ought to have been improved during
3
ought to have being improved during
4
ought to have been improving during
5
ought to have been improves during