古文 二

一夕。群兒戲於院中。明月初上。院中樹影滿地。群兒皆樂。有頃。一兒忽覺有人隨之。甚恐。急告其友。友曰。隨汝之影也。當汝行月下之時。地上遂又汝影。汝何以忘之。

My translation:
one evening a group of children were playing in the middle of the courtyard. The bright moon began to rise. The courtyard was covered with the shadows of the trees. All the boys were happy. after awhile one of the boys felt that a person was following him. He became very frightened. He told his friends. His friends said, the person following you is your shadow. when you walk under moonlight your shadow follows you on the ground. How did you forget this?