判断下面句子中的冠词用的是否正确、如不对、将其圈出并改正、
long,long ago,there was the hill.and there was a old man living there .
I can see a dog .A dog is yellow.
---where is the bag?---it's under the bed.
I have two bikes .One is new .An other is old.
my vase is here.where is the your one?