1.What's the postage for the parcel?

1.What's the postage for the parcel?
How much will it ____ us to ____ the parcel?
2.I'm so busy that I can't go to visit the exhibition with you.
I'm ____ busy ____ bisit the exhibition with you.
3.He worked hard in order t learn English better.
He worked hard ____ ____ he could learn English better.