急-------希望能有详细的讲解,1.Recently I bought an ancient Chinese vas

急-------
希望能有详细的讲解,
1.Recently I bought an ancient Chinese vase,_____was very reasonable
A.which price B.the price of which C.its price D.the price of that
2____is known to everyone,the moon travels round the earth once every month.
A.It B.As C.That D.What
3.____the air is to man,so is water to fish.
A.Since B.Just C.When D.As
4.____the days went on,the situation there got worse.
A.With B.Since C.While D.As
5.The science of medicine,_____progress has been very rapid lately,is perhaps the most important of all the sciences.
A.to which B.in which C.which D.with which