题目

It's a cold day in December. A little boy about 10-year-old was standing in front of a shoe store on Broadway, barefooted, peering through the window, and shivering with cold. A lady approached the boy and said   61   (gentle), My little fellow, why are you looking so earnestly in that window? I was asking God to give me a pair of shoes, the boy __62__ (reply). The lady took him by the hand, went into the store,   63   asked the clerk to get a half dozen pairs of socks for the boy. She then asked   64   he could give her a basin of water and a towel. The clerk quickly bro在△ABC中，a，b，c为内角A，B，C所对的边，且acosB=bcosA，则该三角形一定是A.等边三角形B.直角三角形C.等要直角三角形D.等腰三角形