Gst for builder

A BUILDER TAKE ADVANCE FROM PARTY AND WORK WITH THAT AMOUNT NOW GST APPLICABLE ON ADVANCE FROM PARTY THAT AMOUNT DEPOSIT BY BUILDER AGAINST RECEIPT NOTE GST AVALIBLE FOR INPUT ALSO CONTRACTOR RAISE BILL FOR THEIR WORK AND GST CHARGE IN THE BILL NOW THIS IS ALSO AVALIBLE FOR INPUT 

NOW IST QUESTION IS ITC CAN BE CARRIED FORWARD IN NEXT YEAR ?

2ND QUESTION IS THEN ONE OF THE BIG AMOUNT OF CURRENT CAPITAL OF BUILDER GOING IN THE HAND OF GOVT.? ITS MAY BE EFFECT ON REAL ESTATE