请帮我解决这两个英语问题,
I was born_____August 10th.
A.on            B.in           C.at
There_____a few tall buildings near my home.
        A.is.           B.am         C.are
我写的答案是C,C.可是答案是A,A.我很不解,为什么要填at和are呢?