Good Riddles

Question: What is AD before BC, exams before tests and last year is after last month?

Question: what does not move outside (the surface)but moves inside ?

Question: what have holes but you will see it on the street ?

Question: Only one color, but not one size, Stuck at the bottom, yet easily flies, Present in sun, but not in rain, Doing no harm, and feeling no pain. What am I?

Question: One day, a guy is on the street in the middle of the night , he saw some famous people . He suspect something is not right because the guy saw they are flying so he called a cop .But, the cop immediately went away after he said something to him,after that he knew he is wrong.What did the cop said?(three words)