Mystery: Small needles are big, and big needles are all over the hillside. You can cross Chung Shan Man, but you can't cross rivers.
Analysis: Fire as small as the eye of a needle can spread the whole forest. Fire can't touch water, so you can't cross the river. From these, it can be inferred that the answer to this riddle is fire.
Extended data
Riddle:
1, thin and black-hearted, wearing colorful clothes. Piano, chess, calligraphy and painting are different. Sharpen your head to help you. (type something)-answer: pencil
2, take off the red robe with white clothes, the black fat man under the white clothes (hit a fruit)-answer: litchi.
3, a group of little girls, sitting in the middle of the water, holding green rain umbrellas, all blushed with laughter (hit one)-answer: lotus.
The children are so happy to win the prize in the singing contest (playing a section)-answer: Children's Day.
5, small pieces of paper, emitting a fragrance, restaurants are the most common. Use after meals-answer: napkins.
6, take off the red robe with white clothes, the black fat man under the white clothes (make a fruit)-answer: litchi.