1.已事先询问警察是否有SHORT-TERM停车场;
Police did not give you an answer. He asked you to look for it yourself.
2.本人寻找但未发现任何标识;
Can not find it means you need keep looking. That is not an excuse.
3.应急停车且留人在车中
Leave child in a car is a more serious offense. If you have any brain cell left, dont emphsize that.