COLUMBIA, S.C. (AP) — South Carolina senators started making progress Wednesday on a massive bill that supporters said would overhaul public education.

Senators approved about a dozen changes to the bill which is in its fourth week of debate, including an amendment that would allow districts to set their own dates to start school. Current state law doesn't allow the school year to begin for students before the third Tuesday in August.

Senators also changed the bill to double the amount given to all teachers to buy supplies to $550 a year and to pay the certification costs of first time teachers, which are around $500. Those two proposals would cost about $18 million.

Senators have not indicated when they will begin debating the bill itself.

Over 11 days of debate, senators have also discussed protections for teachers including break time and pay for extra duties and standardized testings.

The bill touches schools of every type and grade level, from prekindergarten to technical schools. The bill also covers administrative issues ranging from standardized testing to school management.

The House passed its own version in March and is passing parts of the larger bill in smaller chunks in case the massive bill doesn't pass the Senate.