In-class assignment

Sushi is a very delicious rice ball. The sushi comes from China where is introduced to Japan in 700 A.D., but in over thousands years it has already become Japanese representative of cooking cultures. Long long ago, the businessman did his grain for the long-distance travel. He put some seafood or meat on the salted rice ball, then make it become oblong. The name of the sushi is due to the sushi tastes sour, Japanese cried out very sour at that time. And they got its pronunciation. Now there are a variety of sushi's categories, such as nigiri sushi, maki sushi, and hako sushi etc.. But it is not cheap in Japan. If you go to Japan, the Japanese will invite you to eat dinner, please don't say just sushi, that will be impoliteness.