Ask a joke. The first one that makes me laugh is for you.

There was a biology exam. Before the exam, the teacher brought a birdcage. The bird cage is covered with black cloth, and only the legs are exposed. The teacher said that the exam questions were to look at the legs and write the names and characteristics of birds. A candidate scolded "What bird did you take the exam" and walked out of the examination room. The teacher stopped the student and said that he ignored the discipline in the examination room and asked him to leave his name. The student smoothed his trouser legs and said, "Guess, guess! ! "